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Smulan
A plane is on a runway that is a giant conveyor belt. As the plane tries to take off, the conveyor will match the plane-wheels' surface speed, opposing the plane's forward motion.

If the wheels and belt have perfect traction, ie no slipping or skidding, will the plane be able to take off?

In this version, the belt's speed B.vx is the same as the wheels' surface speed W.vs, which is the same as (no slipping or skidding) the belt's speed minus the plane's speed W.vx:

B.vx = W.vs = B.vx - W.vx ==> W.vx = 0

i.e. the plane's speed W.vx is 0, and the plane doesn't move and hence doesn't take off. The belt speed (equal to the wheel surface speed) can be anything though.

With idealized components (indestructable and perfectly rigid wheels and belt, perfect traction but no internal friction, sufficient control systems and power, etc), this version of the quiz has no physical meaning - the plane is defined by the question to stand still.

However, since perfect traction cannot occur in an infinitely small (mathematical) contact point, apart from torque a linear force exists between the wheels and belt, which increases with the belt speed.

For any force the plane's engine delivers, there is a (constant) belt speed which produces a matching force backwards, keeping the plane from moving:

* Graph (Final Belt Speed vs Force): up2data.se/get/FBS.gif

Note that, according to this simulation, it seems as if the thrust the plane must deliver to accelerate grows as the cube of the belt's speed.

* Simulation scene (Dax Phyz data file): up2data.se/get/PC.pzs

* Youtube video of simulation: youtu.be/NByJ2n6hbYs
synthsin75
Sounds like a sock puppet with this being the first post.
Smulan
QUOTE (synthsin75+May 6 2011, 11:49 PM)
Sounds like a sock puppet with this being the first post.

It probably does. I'm not, however, just an avid Dax Phyz user.
synthsin75
QUOTE (Smulan+May 6 2011, 06:07 PM)
It probably does. I'm not, however, just an avid Dax Phyz user.

Well, we've had this discussion here, and don't really need it brought up any more than it already has been. You might want to search for related threads, and read a bit of them, before starting a new one.
Subduction Zone
To cut to the chase an accelerating belt can ideally hold a plane in place. A belt at constant velocity cannot.
Smulan
QUOTE (Subduction Zone+May 7 2011, 01:25 AM)
To cut to the chase an accelerating belt can ideally hold a plane in place.  A belt at constant velocity cannot.

I'm afraid I don't agree.

If ideal comprises no internal friction, perfectly rigid components, full traction and nothing but torque from the belt to the wheels, the belt doesn't affect the plane's horizontal movement at all.

With nothing to keep the plane from moving, the belt would not be able to match the wheels' surface speed, which would make the prerequisites contradictory.

If on the other hand we take into account the fact that traction between the belt and wheels does by nescessity induce a linear component, I suggest that the belt does not need to accelerate to keep the plane from moving, but only maintain a constant speed.
synthsin75
Really? You want to do this yet again?
AlexG
OMG, do we have to have still another fu*king thread on this?
Subduction Zone
Smulan you may not agree but all of the math and physics are in previous threads.

synthin75, why not? Nothing much is happening tonight.
synthsin75
QUOTE (Subduction Zone+May 6 2011, 08:15 PM)
synthin75, why not? Nothing much is happening tonight.

Why not keep the BS confined to the existing threads, where you seem to have quit replying?
Subduction Zone
They weren't going anywhere. All of the questions had been answered more than once. I got tired of the denial of various parties.
Smulan
QUOTE (Subduction Zone+May 7 2011, 02:15 AM)
Smulan you may not agree but all of the math and physics are in previous threads.

Oh dear, I must have missed it
I did find a derivation based on rolling friction coupled with some other linear force, the latter in my view undefined (I may very well be mistaken).

Would you agree that in the ideal case (as in no friction, perfectly round wheels on a perfectly flat belt and perfect bearings etc, yet perfect traction), the belt would only make the wheels to rotate?
AlexG
Oh sh1t, here we go again.
Subduction Zone
No, the wheel still would have mass and it would take a force to accelerate it. That results in a reactive force that can keep the plane in place. Once again all the math and physics are in the previous threads. Why don't you read those a bit. Especially posts by Sithdarth.

ETA: I tell you what, I will leave this thread for tonight so that you have some time to read the previous posts.
synthsin75
QUOTE (Subduction Zone+May 6 2011, 08:25 PM)
They weren't going anywhere. All of the questions had been answered more than once. I got tired of the denial of various parties.

More like you finally put your foot in your mouth too far to extricate.
AlexG
QUOTE
That results in a reactive force that can keep the plane in place

In all the previous threads, your 'reactive force' is never shown, just assumed.
Smulan
QUOTE (Subduction Zone+May 7 2011, 02:45 AM)
No, the wheel still would have mass and it would take a force to accelerate it.  That results in a  reactive force that can keep the plane in place.

I can't argue with that.

In any case, I took your advice and read most of Sithdarth's posts, thanks.
For what it's worth, I didn't find any post from him supporting your view above, at least not as succintly worded.

I did find this from Sithdarth:

M_p*A_p = F_thrust - F_belt = F_thrust - I*α/R
X_plane = R*Θ - X_belt
V_plane = R*ω - V_belt
A_p = R*α - A_belt
X_belt = R*Θ
A_belt = R*α
X_plane = 0
V_plane = 0

To me, this is a somewhat cumbersome way of expressing the OP mathematically. The bottom line, V_plane = 0, follows directly from (using Sithdarth's notation):

V_belt = R*ω [OP prerequisite]
R*ω = V_belt - V_plane [wheel surface speed, no slipping]
R*ω = R*ω - V_plane [V_belt = R*ω]
V_plane = 0

Is this the mathematics and physics you refer to?
Beer w/Straw
Subduction Zone
Beer w/Straw, nope, that is not a win for you. The argument is not if the treadmill could stop all planes. If it could keep one plane from taking off that otherwise could fly the concept is proved. This is not a prove for all cases question. It is more of a prove once question. And most planes would not have the power to take off even if you use real life values for traction for the wheels.

Smulan, Sithdarth did a more formal proof. That means, as you can see, more words to say the same thing. If you read enough of his posts you will see that he also has a formula for what acceleration is necessary to keep the plane in place.

Alex G, wrong. It was not assumed. It was demonstrated in more than one way. The amount of force being developed by the belt was derived from known physics. Sithdarth made a proof of concept video. All that has ever been posted by those who disagree with us is simple denial. And here is one very simple way that you can observe this reactive force. If there was no reactive force a cylinder rolling down a ramp would accelerate just as quickly as an object sliding fricitonlessly would. It doesn't. In fact the amount of back force depends on the value of I for the object. A solid wheel or cylinder rolls at 2/3 of the acceleration of a sliding frictionless object, a ring accelerates at 1/2 the rate of a sliding frictionless object. Your implication that such a force does not exist is refuted by those observations.

And last to synthin, I have made mistakes in the past, but none on the order that you have made, so no, I have not put my foot in my mouth too far yet. When I get to your level I would probably leave. Though I am more likely to admit that I am wrong first.
synthsin75
QUOTE (Subduction Zone+May 7 2011, 08:53 AM)
Though I am more likely to admit that I am wrong first.

Nope. Instead of admitting you were wrong, you just quit posting to that thread and waited for someone else to bring it up in a new one. So either admit you were wrong now, or admit you're a liar. Either way.
QUOTE (synthsin75 @ Apr 24 2011+ 10:54 PM)
QUOTE (Subduction Zone @ Apr 24 2011+ 10:20 PM)

Once again, the rotational plane of the ball is the surface it is rolling on.  The rotational plane is not a plane that is at right angles to its axis.

Your above cited reference:
http://en.wikipedia.org/wiki/Plane_of_rotation

And the axis and plane of rotation, from that reference.
User posted image: http://upload.wikimedia.org/wikipedia/commons/0/04/PlaneRotation.svg

Maybe you should try reading your reference, even if you don't bother to read what you are replying to here. Don't you feel foolish now?

Beer w/Straw
QUOTE (Subduction Zone+May 7 2011, 02:53 PM)
Beer w/Straw, nope, that is not a win for you.  The argument is not if the treadmill could stop all planes.  If it could keep one plane from taking off that otherwise could fly the concept is proved.  This is not a prove for all cases question.  It is more of a prove once question.  And most planes would not have the power to take off even if you use real life values for traction for the wheels.

synthsin75
Blather blather blather, you fail me win, blah blah blah.
Subduction Zone
Fine, I made an error about that very minor point synthin. Now why don't you admit that you were wrong about the forces on the plane? The same standards should apply. You have been shown to be wrong in your claims many times over, and yet you persist in repeating your errors.

One more time Beer, that is cute but not what is being discussed.
synthsin75
QUOTE (Subduction Zone+May 7 2011, 11:24 AM)
Fine, I made an error about that very minor point synthin. Now why don't you admit that you were wrong about the forces on the plane? The same standards should apply. You have been shown to be wrong in your claims many times over, and yet you persist in repeating your errors.

A "minor" error that you stubbornly argued about and left that thread without addressing. Even going so far as to insult people who knew and used the proper definition of a term you introduced. So you admit you were wrong, and all of the vitriol you spouted about it was completely unfounded. Good.

I have yet to get far enough to debate the forces on the plane because you have yet to be honest enough to admit that the version you prefer doesn't imply what you say it does. I have proven the reasonable interpretation of the wording you claim to have "parsed" to have no bearing on the one you state as pertaining to your answer.

So you are claiming an error in what I haven't yet been given a clearly enough stated assertion to make any claims on at all. I've asked umpteen times for you to just state the question as you are forced to interpret it to arrive at your answer, but you just want to deny and sling vitriol just as you've admitted doing in this case.

I sense a pattern that you have at least verified here. Thank you.
Subduction Zone
You have proven nothing synthin and now we know who the real phony is. You tried to play semantics with the Russian version and failed. The only people who have trouble parsing the Russian version are those who can't do the physics that show how the belt keeps the plane in place. I don't know how to help you with something that is self evident to me. It is sort of like if some asks you "If I pick up this brick and then drop it will it fall down?" I answer "Yes" and then they ask what I mean by that.

It took Sythdarth many attempts before you would even accept the fact that an accelerating belt would impart a force on the plane. Once you finally seemed to admit that your personal prejudice against the plane not flying made you try to reinterpret the Russian version. One of the reasons I quit posting on the other side was due to the dishonesty I saw from you and your friends.
synthsin75
QUOTE (Subduction Zone+May 7 2011, 12:30 PM)
You have proven nothing synthin and now we know who the real phony is. You tried to play semantics with the Russian version and failed. The only people who have trouble parsing the Russian version are those who can't do the physics that show how the belt keeps the plane in place. I don't know how to help you with something that is self evident to me. It is sort of like if some asks you "If I pick up this brick and then drop it will it fall down?" I answer "Yes" and then they ask what I mean by that.

It took Sythdarth many attempts before you would even accept the fact that an accelerating belt would impart a force on the plane. Once you finally seemed to admit that your personal prejudice against the plane not flying made you try to reinterpret the Russian version. One of the reasons I quit posting on the other side was due to the dishonesty I saw from you and your friends.

No, the original confusion with what SD was asserting was ALL ABOUT the erroneous interpretation of the Russian version that runs counter to ANY reasonable "parsing" of the meaning of the wording used. Your interpretation of the wording is "self evident" in your subjective self-delusion, and it is that which doesn't provide you with any means to justify your interpretation. I provided very clear definitions throughout my "parsing". You simply want to interpret it in a way that makes your assumptions, and thus your answer, valid. Between a supported interpretation and an unsupported one, we'll go with the supported one.

If you'd ever get over this self-deception, only then could I address you answer in the context of a properly stated question. There is no "reinterpretation", only your faulty initial interpretation.

Blather blather BS, you're wrong, I'm right, tough noogies, blah blah blah. We've heard it all before. It's old, it's tired. Give it a rest. Find some other way to prove you self-worth.
Subduction Zone
Sorry, I skipped over most of your nonsense. I am not interested in any of your justifications for your bad behavior. I tell you what, why don't you write an interpretation of the Russian version and I will tell you where you are wrong.
synthsin75
QUOTE (Subduction Zone+May 7 2011, 02:10 PM)
Sorry, I skipped over most of your nonsense.  I am not interested in any of your justifications for your bad behavior.  I tell you what, why don't you write an interpretation of the Russian version and I will tell you where you are wrong.

Yes, the deluded don't often like to confront anything about their self-deception, that's exactly how they keep it intact. I know, you're too busy with your own justifications to yourself to be bothered. You've told everyone under the sun that their wrong so many times without any justification that it is completely meaningless from you. Might as well be a knee jerk reaction for all the validity it implies.

So I'll tell YOU what. You just be satisfied to be king in your own mind, no one else is buying it. I've already given you every opportunity to just make a simple statement of the question in the exact words needed to justify your answer. You use the wording of you "interpretation" so often that I cannot fathom why you absolutely refuse to just use that wording.

You're working against yourself.

Obviously no amount of new threads on this subject are EVER going to get anywhere.
Subduction Zone
See, you can't even follow up to a simple request. That again shows your dishonesty. There was a new person who was interested in this problem and that is why I came back. You have lost this debate many times over. Unless you come up with something new I will be happy to point out that your errors have already been dealt with.
synthsin75
My only real interest here is to see if you are gracious enough to let a topic that only you and boit seem interested in continuing die out. You and I both know that nothing good can possibly come of it, as history has proven, and as you have so exquisitely shown.

But go ahead. Blather on. If you must. Just keep the definition of insanity in mind. You know, the "expecting different results" part.

Subduction Zone
Why would I want to let it die out? Nothing good comes from it only when you run into people who are willing to deny basic physics and continue to do so long after they are shown to be wrong. If some newbie comes along and has a genuine interest in the topic I don't mind discussing it with them. I don't expect you to apologize for your past bad behavior or to change anytime in the near future. I am merely going to keep reminding you and others of it.

And once again. like many mentally ill people will do, you are projecting. It is your and other deniers behavior that caused all of the problems with these threads. If you limited your discussion to the physics this would have been resolved long ago. But you have a strange disease where you don't want to allow other people to show you that you are wrong. If you don't like this topic why don't you "let it die"?
synthsin75
QUOTE (Subduction Zone+May 7 2011, 03:17 PM)
I don't expect you to apologize for your past bad behavior or to change anytime in the near future. I am merely going to keep reminding you and others of it.

Remember that aforementioned definition of sanity?
Subduction Zone
Like I said, this is not for your benefit that I am posting here. You will never learn, you have shown that you are not willing to do so. But I am happy to post about your hypocrisy whenever you do post here.
Beer w/Straw
Draw a diagram.
Smulan
According to this simulation, it seems as if the thrust the plane must deliver to accelerate grows as the cube of the belt's speed.

* Graph (Final Belt Speed vs Force): up2data.se/get/FBS.gif

* Simulation scene (Dax Phyz data file): up2data.se/get/PC.pzs

* Youtube video of simulation: youtu.be/NByJ2n6hbYs
Beer w/Straw
I actually meant Free Body Diagram but who's counting
Subduction Zone
I don't have the tech savy to do a Free Body Diagram, but I can show you a link that has a wheel on a ramp rolling without friction and its FBD. It only takes a change of frame of reference to see how this applies to the airplane on a conveyor belt.Linky. Go to page 2 for your diagram.
egnorant
Wow, the criteria of the original post is very limited.
The belt can go any speed it likes.
The wheels don't skid or slip.
The plane doesn't move.

Will the plane take off?

No

Beer w/Straw
Well, since no signal can travel faster than light and if the conveyor is at the longest distance for the force to reach, given enough runway the plane will always take off.
Subduction Zone
Yes, this version is rather self defining. But the question is does the belt impart a force to the plane above and beyond that of rolling resistance and the answer is yes. An accelerating belt will place a force on the plane proportional to the acceleration.

Now for Beer's claim. Nope, even if the belt can hold together at relativistic speeds the plane cannot take off. Nothing with a nonzero rest mass can be accelerated to the speed of light, so the value of I for the wheels will increase as the speed of the belt approaches light speed, and therefore it will take a lower acceleration to keep the plane in place. The belt can keep accelerating forever, it will be accelerating at a slower and slower rate as it gets near to the speed of light.
Beer w/Straw
ugh !

I'm talking about the plane moving an infintesimally small distance forward before the reaction of the belt kicks in.

So in essence if previous arguments of the plane not flying were corect, I'm saying "Ya, but if the runway was 1000 billion kilometres long you'd be wrong!"

Subduction Zone
And why do you think that the plane would move forward in the first place?
Beer w/Straw
QUOTE (Subduction Zone+May 9 2011, 04:18 AM)
And why do you think that the plane would move forward in the first place?

Because it isn't absolute 0.
Subduction Zone
QUOTE (Beer w/Straw+May 9 2011, 05:21 AM)

Because it isn't absolute 0.

Do you understand the concept of a thought problem?
synthsin75
QUOTE (Subduction Zone+May 9 2011, 11:54 AM)
Do you understand the concept of a thought problem?

Yeah, BWS! You should already know that in any thought problem we can ignore anything we like to arrive at a foregone conclusion. Don't even try to dispute it!
Subduction Zone
Not exactly synthin. In a thought problem you can ignore certain parts of the problem. The main concept behind this one is that an accelerating belt can hold a plane in place. The rest would be engineering details, some quite significant, but that is all they are.
synthsin75
QUOTE (Subduction Zone+May 9 2011, 02:21 PM)
Not exactly synthin. In a thought problem you can ignore certain parts of the problem. The main concept behind this one is that an accelerating belt can hold a plane in place. The rest would be engineering details, some quite significant, but that is all they are.

You really don't know what sarcasm is, do you?

Instead of perhaps trying to explain how you can ignore what BWS brought up, you dodge this and question whether he understands how YOU ignore it. So that begs the question, how DO YOU ignore it?
Sithdarth
Getting exact matching instantly is as simple as getting the accelerations and velocities to be exactly equal. People seem to have this crazy ideal that the belt was built by a ***** and has no way of extrapolating the future speed of the belt from the past speed of the belt. Anyone dumb enough to build a system designed to maintain any sort of equilibrium that does not build in predictive ability doesn't deserve to be designing anything. Its almost impossible in the real world to maintain equilibrium without a predictive component.

Of course if you use the term infinitesimal you've immediately left any real world considerations behind. Infinitesimal quantities are purely mathematical. If you move an infinitesimal distance then you have moved zero distance. That is what infinitesimal means mathematically.
Beer w/Straw
QUOTE (Subduction Zone+May 9 2011, 05:54 PM)
Do you understand the concept of a thought problem?

Do you understand I'm being deliberately ridiculous?
synthsin75
QUOTE (Sithdarth+May 9 2011, 05:45 PM)
Getting exact matching instantly is as simple as getting the accelerations and velocities to be exactly equal. People seem to have this crazy ideal that the belt was built by a ***** and has no way of extrapolating the future speed of the belt from the past speed of the belt. Anyone dumb enough to build a system designed to maintain any sort of equilibrium that does not build in predictive ability doesn't deserve to be designing anything. Its almost impossible in the real world to maintain equilibrium without a predictive component.

How is predictive reaction specified in the Russian wording you so tout?
QUOTE
Of course if you use the term infinitesimal you've immediately left any real world considerations behind. Infinitesimal quantities are purely mathematical. If you move an infinitesimal distance then you have moved zero distance. That is what infinitesimal means mathematically.

Infinitesimals add up to finite quantities.
Sithdarth
QUOTE

How is predictive reaction specified in the Russian wording you so tout?

It's not specified exactly but then again the Russian wording is pure thought problem where things can happen instantly and where we don't worry about any delay. The only time you need a predictive system is when people say things like "in the real world it takes some amount of time for the belt to react" at which point they have deviated from the wording of the problem. Therefor the only possible responses are to tell them they deviated from the problem which basically never works, or to deviate from the problem yourself which is marginally more successful if the person you are dealing with is in anyway reasonable.

The other side of this is that the wording itself is so absurdly vague that it is largely up to the interpretation of the reader what is and isn't part of the problem statement. Personally I know from experience that it is simply bad engineering to ever build a system that attempts to maintain equilibrium without a predictive element. When you do that you generally end up with a system that once it goes far enough off the equilibrium cannot recover. You can't always prevent this with a predictive system but a predictive system increases the likely hood that you can. To me its perfectly obvious that no system that attempts to maintain an equilibrium should ever be built without some predictive component to it and therefor I naturally include it in all such systems I design.

QUOTE (->
 QUOTE How is predictive reaction specified in the Russian wording you so tout?

It's not specified exactly but then again the Russian wording is pure thought problem where things can happen instantly and where we don't worry about any delay. The only time you need a predictive system is when people say things like "in the real world it takes some amount of time for the belt to react" at which point they have deviated from the wording of the problem. Therefor the only possible responses are to tell them they deviated from the problem which basically never works, or to deviate from the problem yourself which is marginally more successful if the person you are dealing with is in anyway reasonable.

The other side of this is that the wording itself is so absurdly vague that it is largely up to the interpretation of the reader what is and isn't part of the problem statement. Personally I know from experience that it is simply bad engineering to ever build a system that attempts to maintain equilibrium without a predictive element. When you do that you generally end up with a system that once it goes far enough off the equilibrium cannot recover. You can't always prevent this with a predictive system but a predictive system increases the likely hood that you can. To me its perfectly obvious that no system that attempts to maintain an equilibrium should ever be built without some predictive component to it and therefor I naturally include it in all such systems I design.

Infinitesimals add up to finite quantities.

Some do and some don't. For example the Cantor set. There are an infinite number of sets with infinitesimal length left over in the Cantor set but the sum of that infinite number of infinitesimal lengths is still zero. One should not attempt to use mathematical concepts that one does not fully understand.
NoCleverName
QUOTE (Sithdarth+May 9 2011, 08:36 PM)

It's not specified exactly but then again the Russian wording is pure thought problem where things can happen instantly and where we don't worry about any delay.

Nobody is interested in your self-serving interpretation of the problem that allows your "cheat" system to work.
Subduction Zone
QUOTE (Beer w/Straw+May 9 2011, 11:57 PM)
Do you understand I'm being deliberately ridiculous?

You may very well be, but unfortunately some of your ridiculous points are taken seriously by the likes of synthin.
Subduction Zone
QUOTE (NoCleverName+May 10 2011, 01:16 AM)
Nobody is interested in your self-serving interpretation of the problem that allows your "cheat" system to work.

Wrong again NCN. It is not cheating to take a thought problem literally. I hope by now you can see that an accelerating belt can apply a force to the plane. If its acceleration was high enough you could move the plane backwards. So keeping the plane in place would only take the right control system.
Dabeer
QUOTE (RealityCheck+May 9 2011, 09:23 PM)
However, according to Sithdarth et al, now that we have added the non-slipping idler wheels, these wheels and the axles they are mounted on are supposed to be subject to a SUBSTANTIAL translational force in the direction of the belt acceleration (ie, supposedly horizontally across the floor in the direction the upper surface of the belt is moving in).

So Sithdarth et al will have us believe that by the mere addition of idler wheels in non-slip contact with the upper surface of the belt will propel the whole assembly across the room!

Um... no. The forces will be balanced, and the assembly should remain motionless. The axles of the idle wheels may impart a torque on the frame, but the linear forces (accelerating the wheels and the resistance of the wheels to acceleration pushing back on the belt) should remain in balance.

Now, if there were two frames mounted on top of one another, belt on one, and idler wheels on the other, and with a frictionless interface, you could expect the top to move in one direction and the bottom to move in the opposite.

Sithdarth et al feel free to correct me if my understanding is incorrect.
Sithdarth
QUOTE
So Sithdarth et al will have us believe that by the mere addition of idler wheels in non-slip contact with the upper surface of the belt will propel the whole assembly across the room!

The question Sithdarth et al will have to answer then:

Where does the A-symmetric as well as Substantial force comes from that drives the whole system across the floor now....but which was absent when the idler wheels were not there?

You stopped analyzing the forces too soon. The belt places a backward force on the wheels. However the wheels are attached to the box which then places a forward force on the axles to keep everything in place. Basically what you've made is someone trying to lift themselves by pulling on their boot straps.

-------------------------------------------------------------------------------

QUOTE (->
 QUOTE So Sithdarth et al will have us believe that by the mere addition of idler wheels in non-slip contact with the upper surface of the belt will propel the whole assembly across the room!The question Sithdarth et al will have to answer then:Where does the A-symmetric as well as Substantial force comes from that drives the whole system across the floor now....but which was absent when the idler wheels were not there?

You stopped analyzing the forces too soon. The belt places a backward force on the wheels. However the wheels are attached to the box which then places a forward force on the axles to keep everything in place. Basically what you've made is someone trying to lift themselves by pulling on their boot straps.

-------------------------------------------------------------------------------

Um... no. The forces will be balanced, and the assembly should remain motionless. The axles of the idle wheels may impart a torque on the frame, but the linear forces (accelerating the wheels and the resistance of the wheels to acceleration pushing back on the belt) should remain in balance.

Now, if there were two frames mounted on top of one another - belt on one, and idler wheels on the other - and with a frictionless interface, you could expect the top to move in one direction and the bottom to move in the opposite.

Sithdarth et al feel free to correct me if my understanding is incorrect.

Exactly this.

----------------------------------------------------------------------------------

QUOTE
Nobody is interested in your self-serving interpretation of the problem that allows your "cheat" system to work.

How exactly is my interpretation any more biased than the interpretation of anyone else?

You've committed what could be called an Appeal to Motive.

------------------------------------------------------------------------------------

QUOTE (->
 QUOTE Nobody is interested in your self-serving interpretation of the problem that allows your "cheat" system to work.

How exactly is my interpretation any more biased than the interpretation of anyone else?

You've committed what could be called an Appeal to Motive.

------------------------------------------------------------------------------------

Hi Dabeer.

I was waiting for Sithdarth et al to come back with that very observation. smile.gif

In which case I would observe that because of that the translational forces are opposite and equal between wheel and belt, and the belt cannot accelerate unconstrainedly as in their 'thought problem' construct/claims.

So then in he plane-on-conveyor belt case the plane axle is translating its wheel horizontally while the inertia/momentum forces between the belt and plane wheel in reality would cancel out at every 'instant' of acceleration.

Hence it doesn't matter what is happening between wheel and belt while the plane pushes the axle forward.

This would be wrong. The acceleration of the belt is never unconstrained. It is in fact always a certain constant value. The certain constant value is what causes the force from the belt. There is no unconstrained acceleration anywhere in the system. The existence of the wheels and the spinning of the belt by them does mean that it requires more force to accelerate the belt at the proper constant acceleration. This effect in no way prevents the belt from accelerating. For if the belt's acceleration slowed by any amount from the required acceleration to produce the force need the balance of forces would no longer exist. At which point the belt would be free to return to it's previous acceleration. Of course no such effect exists because the acceleration is constant and the force is constant so it only requires a constant amount of extra force to give the belt the right acceleration.

Edit: Oh and word salad never ever ever beats mathematics and video evidence. If you want to disprove the point I have made disprove the evidence I have presented. Nothing else is going to do it.
synthsin75
QUOTE (Sithdarth+May 9 2011, 06:36 PM)
QUOTE (syn+)
How is predictive reaction specified in the Russian wording you so tout?

It's not specified exactly but then again the Russian wording is pure thought problem where things can happen instantly and where we don't worry about any delay.

Nope.
QUOTE
The aircraft (jet or screw) stands on the tarmac with a movable cover (type transporter). Movement of [Dvigaetsya] coating may be against the direction of take-off aircraft. It has a control system that monitors and adjusts the speed of cloth so that the wheel speed aircraft was equal to the speed blade motion. Question: Can the plane take a run on the track and take off?

How does "monitors and adjusts" mean instant?

monitor - to observe, record, or detect (an operation or condition) with instruments that have no effect upon the operation or condition.

adjust - to change (something) so that it fits, corresponds, or conforms; adapt; accommodate

Bare minimum of speed of light delay to observe or detect, much less apply.

If it's meant to be a pure thought problem, rather than a simple and trivial riddle, then the exact wording cannot be altered and must apply, as it would have been intended to do as an intended thought problem.
QUOTE (->
 QUOTE The aircraft (jet or screw) stands on the tarmac with a movable cover (type transporter). Movement of [Dvigaetsya] coating may be against the direction of take-off aircraft. It has a control system that monitors and adjusts the speed of cloth so that the wheel speed aircraft was equal to the speed blade motion. Question: Can the plane take a run on the track and take off?

How does "monitors and adjusts" mean instant?

monitor - to observe, record, or detect (an operation or condition) with instruments that have no effect upon the operation or condition.

adjust - to change (something) so that it fits, corresponds, or conforms; adapt; accommodate

Bare minimum of speed of light delay to observe or detect, much less apply.

If it's meant to be a pure thought problem, rather than a simple and trivial riddle, then the exact wording cannot be altered and must apply, as it would have been intended to do as an intended thought problem.
The only time you need a predictive system is when people say things like "in the real world it takes some amount of time for the belt to react" at which point they have deviated from the wording of the problem.

No deviation, other than from your completely arbitrary choice of what wording is meant to apply as stated.
QUOTE
Therefor the only possible responses are to tell them they deviated from the problem which basically never works, or to deviate from the problem yourself which is marginally more successful if the person you are dealing with is in anyway reasonable.

Like we have told you, nay proven, that you have so deviated. And yep, never works.
QUOTE (->
 QUOTE Therefor the only possible responses are to tell them they deviated from the problem which basically never works, or to deviate from the problem yourself which is marginally more successful if the person you are dealing with is in anyway reasonable.

Like we have told you, nay proven, that you have so deviated. And yep, never works.
The other side of this is that the wording itself is so absurdly vague that it is largely up to the interpretation of the reader what is and isn't part of the problem statement.

The wording only seems vague to those they do not suit.
QUOTE
Personally I know from experience that it is simply bad engineering to ever build a system that attempts to maintain equilibrium without a predictive element. When you do that you generally end up with a system that once it goes far enough off the equilibrium cannot recover. You can't always prevent this with a predictive system but a predictive system increases the likely hood that you can. To me its perfectly obvious that no system that attempts to maintain an equilibrium should ever be built without some predictive component to it and therefor I naturally include it in all such systems I design.

And why, after shouting down ever single engineering consideration, is this the only one acceptable? It is obviously not a "minimal engineering consideration", as the explicit wording counters a predictive system. So it is just an arbitrary addition in an attempt to justify a foregone conclusion, which is exactly why you are continuously asked to reword the question you are asking.

You just cannot, beyond mere self-delusion:
1. Counter the explicit wording of a (claimed by you) pure thought problem
2. Add more than (claimed by you) "minimal" engineering considerations to a pure thought problem

Since the one engineering consideration you try to add violates the first, it is not valid.

So either it isn't a proper pure thought problem, which would require stating one beforehand, or it must be worked as stated, assumed a pure, properly stated, thought problem.
QUOTE (->
 QUOTE Personally I know from experience that it is simply bad engineering to ever build a system that attempts to maintain equilibrium without a predictive element. When you do that you generally end up with a system that once it goes far enough off the equilibrium cannot recover. You can't always prevent this with a predictive system but a predictive system increases the likely hood that you can. To me its perfectly obvious that no system that attempts to maintain an equilibrium should ever be built without some predictive component to it and therefor I naturally include it in all such systems I design.

And why, after shouting down ever single engineering consideration, is this the only one acceptable? It is obviously not a "minimal engineering consideration", as the explicit wording counters a predictive system. So it is just an arbitrary addition in an attempt to justify a foregone conclusion, which is exactly why you are continuously asked to reword the question you are asking.

You just cannot, beyond mere self-delusion:
1. Counter the explicit wording of a (claimed by you) pure thought problem
2. Add more than (claimed by you) "minimal" engineering considerations to a pure thought problem

Since the one engineering consideration you try to add violates the first, it is not valid.

So either it isn't a proper pure thought problem, which would require stating one beforehand, or it must be worked as stated, assumed a pure, properly stated, thought problem.
Some do and some don't. For example the Cantor set. There are an infinite number of sets with infinitesimal length left over in the Cantor set but the sum of that infinite number of infinitesimal lengths is still zero. One should not attempt to use mathematical concepts that one does not fully understand.

You'd have to show how that applies in this case to have any relevance at all. But kind of moot, as per the above.
Dabeer
QUOTE (RealityCheck+May 9 2011, 09:59 PM)
In which case I would observe that because of that the translational forces are opposite and equal between wheel and belt, and the belt cannot accelerate unconstrainedly as in their 'thought problem' construct/claims.

But while the force on the axle of the wheels applies to the mass of the plane, the force pushing back on the belt applies to the mass of the earth. F=ma, and since m(plane) < m(earth) by a HUGE margin, the result would be a stationary belt and a moving plane. Or, rather, in this case, a stationary plane, since F(belt on wheels) = F(thrust).
synthsin75
QUOTE (Subduction Zone+May 9 2011, 07:42 PM)
Wrong again  NCN.  It is not cheating to take a thought problem literally.

Except you haven't.

QUOTE (SD+)
QUOTE (NCN+)

Nobody is interested in your self-serving interpretation of the problem that allows your "cheat" system to work.

How exactly is my interpretation any more biased than the interpretation of anyone else?

You've committed what could be called an Appeal to Motive.

No, as I've shown, he is correct to call your interpretation self-serving, and thus not an Appeal to Motive. Why do you always fall back to accusation of logical fallacy when you cannot back your claims?
Subduction Zone
We have gone through this delay that you want to introduce before synthin and you would not answer the key questions then. You probably will not answer the key questions now. So you want to introduce a delay, by this I mean that you are claiming that the belt does not react instantaneously. So one more time, after the wheels start rolling how long does it take for the belt to react? Will it react some time tomorrow?
Dabeer
QUOTE (RealityCheck+May 9 2011, 10:32 PM)
.
Hi Dabeer.

I refer to my example where the whole thing is on a frictionless floor instead of bolted to the ground. So, would the outcome be different if the plane-on-belt system was on a frictionless floor?
.

Your proposed scenario is not analogous to a plane on a treadmill because the idler wheels are attached to the same frame that the belt is attached to. There is no relative motion possible between the axles of the wheel and the axles of the belt.

If the belt were on a frictionless surface, and the plane were free to move relative to the belt, then yes the belt system would move, and probably wouldn't be able to stop the plane.
synthsin75
QUOTE (Subduction Zone+May 9 2011, 08:43 PM)
We have gone through this delay that you want to introduce before synthin and you would not answer the key questions then. You probably will not answer the key questions now. So you want to introduce a delay, by this I mean that you are claiming that the belt does not react instantaneously. So one more time, after the wheels start rolling how long does it take for the belt to react? Will it react some time tomorrow?

If you had bothered to read, which I know you don't, I made it very clear that a minimum delay is that which takes light to traverse the distance from the wheel monitored through the control system and to the belt motors it adjusts.

Now quit crowing about this like it's some major victory DS.
NoCleverName
QUOTE (Sithdarth+May 9 2011, 08:36 PM)
To me its perfectly obvious that no system that attempts to maintain an equilibrium should ever be built without some predictive component to it and therefor I naturally include it in all such systems I design.

Fine. Let's see your design for predicting how a plane that doesn't move will move in the future.
NoCleverName
I see that the subtlety in RC's system has been overlooked. The "idler" wheels should be subjected to the magic force that is supposed to hold back the plane. Now, since without these wheels the cart would already "run in place" (exactly like a runner would do if on a similar treadmill) then this EXTRA opposing force should somehow push the cart backwards ... at least according to Darth's theory.

Subduction Zone
NCN, you should not use prejudicial terms, they affect your thinking process. In the case of the plane on the conveyor belt the wheels are in no way "idler wheels". It has been demonstrated many times how an accelerating belt will apply a transverse force to an object rolling without slipping.

synthing, yes we have admitted in real life many times that there would be delays. But then you could also have a control system that could account for the delay. The thing is that there is not delay mentioned in the Russian version and there is no need to put one in the thought problem. Unimportant items can be ignored. The delay is not important since it would result in a minimal displacement.
Sithdarth
QUOTE
QUOTE
The aircraft (jet or screw) stands on the tarmac with a movable cover (type transporter). Movement of [Dvigaetsya] coating may be against the direction of take-off aircraft. It has a control system that monitors and adjusts the speed of cloth so that the wheel speed aircraft was equal to the speed blade motion. Question: Can the plane take a run on the track and take off?

How does "monitors and adjusts" mean instant?

That is only one of the many possible translations from Russian. Some have the word instant in them others don't. Of course there are people here that take the term match or equal quite literally. Which means at ever instant the speeds must be the same. Which means if you insist on a purely reactionary system means the reaction must be instant.

This requirement is relaxed once you allow for a predictive system.

QUOTE (->
 QUOTE QUOTEThe aircraft (jet or screw) stands on the tarmac with a movable cover (type transporter). Movement of [Dvigaetsya] coating may be against the direction of take-off aircraft. It has a control system that monitors and adjusts the speed of cloth so that the wheel speed aircraft was equal to the speed blade motion. Question: Can the plane take a run on the track and take off?How does "monitors and adjusts" mean instant?

That is only one of the many possible translations from Russian. Some have the word instant in them others don't. Of course there are people here that take the term match or equal quite literally. Which means at ever instant the speeds must be the same. Which means if you insist on a purely reactionary system means the reaction must be instant.

This requirement is relaxed once you allow for a predictive system.

monitor - to observe, record, or detect (an operation or condition) with instruments that have no effect upon the operation or condition.

adjust - to change (something) so that it fits, corresponds, or conforms; adapt; accommodate

Bare minimum of speed of light delay to observe or detect, much less apply.

If it's meant to be a pure thought problem, rather than a simple and trivial riddle, then the exact wording cannot be altered and must apply, as it would have been intended to do as an intended thought problem.

I would ask you what part of this says that the system cannot be predictive? In what way is predicting where something will be in the future and changing a quantity to equal that future value not covered by the definition of adjust? You've changed something so that it fits, corresponds, or conforms to something else. The term adjust does not specify in any way shape or form by what mechanism the adjustment should be achieved. A predictive adjustment is exactly as valid as a reactive adjustment.

QUOTE
No deviation, other than from your completely arbitrary choice of what wording is meant to apply as stated.

You do realize all choices of interpretation of the wording are equally arbitrary. Well except for those translations with the word instant. But either way there interpretations in which the results described in the wording can be obtained and for the sake of argument it is generally better to go with the option that can be discussed over the option where no discussion is possible.

QUOTE (->
 QUOTE No deviation, other than from your completely arbitrary choice of what wording is meant to apply as stated.

You do realize all choices of interpretation of the wording are equally arbitrary. Well except for those translations with the word instant. But either way there interpretations in which the results described in the wording can be obtained and for the sake of argument it is generally better to go with the option that can be discussed over the option where no discussion is possible.

Like we have told you, nay proven, that you have so deviated. And yep, never works.

No such thing has come remotely close to happening. The only thing that is happened is people complaining about me being arbitrary and biased while being equally arbitrary and biased and refusing to acknowledge that they are being arbitrary and biased.

QUOTE
The wording only seems vague to those they do not suit.

Prove it. See the above statement about people accusing me of being biased and arbitrary while being biased and arbitrary and refusing to see it.

QUOTE (->
 QUOTE The wording only seems vague to those they do not suit.

Prove it. See the above statement about people accusing me of being biased and arbitrary while being biased and arbitrary and refusing to see it.

And why, after shouting down ever single engineering consideration, is this the only one acceptable?

It isn't. However it is the only one that allows any discussion to occur and therefore for the sake of argument its the one we should be focused on. At the very least it prevents anyone from saying this is impossible because there is one way that it is possible.

QUOTE
It is obviously not a "minimal engineering consideration", as the explicit wording counters a predictive system.

How exactly?

QUOTE (->
 QUOTE It is obviously not a "minimal engineering consideration", as the explicit wording counters a predictive system.

How exactly?

So it is just an arbitrary addition in an attempt to justify a foregone conclusion, which is exactly why you are continuously asked to reword the question you are asking.

It isn't an addition it is a difference of interpretation. Something you seem unable to understand just like you can't understand how all your arguments about this point are based in equally arbitrary and biased reasoning.

QUOTE
You just cannot, beyond mere self-delusion:
1. Counter the explicit wording of a (claimed by you) pure thought problem
2. Add more than (claimed by you) "minimal" engineering considerations to a pure thought problem

I am doing neither. No place in the wording is a predictive system prohibited. You simply cannot admit to being wrong and so you attempt to force your interpretation as the only one possible when it isn't. I simply put mine forward for the sake of argument because it is the only why to actually have a discussion on the topic.

QUOTE (->
 QUOTE You just cannot, beyond mere self-delusion:1. Counter the explicit wording of a (claimed by you) pure thought problem2. Add more than (claimed by you) "minimal" engineering considerations to a pure thought problem

I am doing neither. No place in the wording is a predictive system prohibited. You simply cannot admit to being wrong and so you attempt to force your interpretation as the only one possible when it isn't. I simply put mine forward for the sake of argument because it is the only why to actually have a discussion on the topic.

Since the one engineering consideration you try to add violates the first, it is not valid.

Prove it.

QUOTE
So either it isn't a proper pure thought problem, which would require stating one beforehand, or it must be worked as stated, assumed a pure, properly stated, thought problem.

I totally did the latter. You simply refuse to see it because of your bias.

QUOTE (->
 QUOTE So either it isn't a proper pure thought problem, which would require stating one beforehand, or it must be worked as stated, assumed a pure, properly stated, thought problem.

I totally did the latter. You simply refuse to see it because of your bias.

You'd have to show how that applies in this case to have any relevance at all. But kind of moot, as per the above.

You really know that little about math? What are you even doing here?

Anyway the point is that if you want to state that a summation of infinitesimal quantities equals something other than zero you have to prove that it does. You can't simply assume that it does equal something other than zero. Generally speaking infinitesimal summations add to finite values as well. So that not only do you have to prove the summation is not zero you also have to prove that it is infinite.

All this means that any argument involving the addition of a series of infinitesimal displacements and how that effects the plane's motion requires a mathematical proof that said infinitesimals actually sum to a finite value.

-------------------------------------------------------------------------

QUOTE
Fine. Let's see your design for predicting how a plane that doesn't move will move in the future.

Simple you predict the future speed of the wheel not the future linear motion of the plane. Which should be intuitively obvious to any non-biased observer who is actually considering the point being made and not simply relying on knee jerk reactions.

QUOTE (->
 QUOTE Fine. Let's see your design for predicting how a plane that doesn't move will move in the future.

Simple you predict the future speed of the wheel not the future linear motion of the plane. Which should be intuitively obvious to any non-biased observer who is actually considering the point being made and not simply relying on knee jerk reactions.

I see that the subtlety in RC's system has been overlooked. The "idler" wheels should be subjected to the magic force that is supposed to hold back the plane. Now, since without these wheels the cart would already "run in place" (exactly like a runner would do if on a similar treadmill) then this EXTRA opposing force should somehow push the cart backwards ... at least according to Darth's theory.

Wrong. The idler wheels have no thrust force at all in his example. The counter force comes from the attachment of the idler wheels to the frame. But as the wheels press against the frame the frame presses against the wheel and as the belt presses on the wheel the wheel presses on the belt which presses on the frame. In the end everything cancels out.
------------------------------------------------------------------------------

QUOTE
Anyhow, the other 'engineering' aspect I want to highlight that is irremovable from Sithdarth analysis is the fact that the belt is connected directly to the earth 'reaction mass' via non-slip contacts from belt to drive wheels to frame to earth.

This in NOT the case for the wheel-to-plane/axle connection.....which is frictionless....and hence essentially presents a frictionlessly SLIPPING contact at the wheel-axle interface.

I tried to highlight this before by using the CASTOR-like wheel system where the fixed and slipping axle is most of the wheel radius.....and the outermost layer of tread being essentially a thin ring. Accelerating the ring which is slipping and isolated far from the plan-axle centre of mass means that there is little force on the axle; especially since the plane is not connected to the moving outer layer of the castor wheel as the earth is connected to the belt layer.

Good thing the force transmission form wheel to axle has nothing to do with friction between the wheel and the axle seeing as the force is applied perpendicular to the axle/wheel interface. It is essentially a normal force which exists regardless of any friction.

Oh and as I've already stated for your ring system if the axle and the center of mass of the ring accelerate at different rates then the axle must eventually pass through the mass of the wheel which can't happen. Either the axle accelerates at exactly the same rate as the center of mass of the wheel or the wheel breaks. Your assertion requires the wheel breaks.

NoCleverName
QUOTE (Subduction Zone+May 9 2011, 11:37 PM)
NCN, you should not use prejudicial terms, they affect your thinking process. In the case of the plane on the conveyor belt the wheels are in no way "idler wheels". It has been demonstrated many times how an accelerating belt will apply a transverse force to an object rolling without slipping.

You really aren't paying attention, are you? Oh, and thanks for verifying what I said: RC's non-powered wheels on his cart are subject to a transverse force. Now, why doesn't his cart move backwards?
Sithdarth
QUOTE
You really aren't paying attention, are you? Oh, and thanks for verifying what I said: RC's non-powered wheels on his cart are subject to a transverse force. Now, why doesn't his cart move backwards?

You should use the post preview button before you post and look for other posts before you post. That way you can avoid putting your foot in your mouth like this.
NoCleverName
You're a real joke, darth. So your "magic force" suddenly disappears if the plane is all of a sudden a car instead? Ha ha. And, to boot, now you're an expert in the Russian language telling us about all the "alternative translations". One wonders how the Russians themselves ever did any engineering with such a sloppy, ambiguous language.

Still waiting for your "design" that predicts what the future speed of the wheel is going to be. And, remember, since you have told us that you have personally designed numerous control systems, I'm sure you'll have no trouble outlining it in sufficient detail that we can verify it ... maybe even build one at home.
NoCleverName
QUOTE (Sithdarth+May 9 2011, 11:58 PM)

You should use the post preview button before you post and look for other posts before you post. That way you can avoid putting your foot in your mouth like this.

Did your little friend SD not say "It has been demonstrated many times how an accelerating belt will apply a transverse force to an object rolling without slipping."?

Are not the idler wheels "rolling without slipping"? So, where is the transverse force? Why isn't it pushing the cart backwards?
synthsin75
QUOTE (Subduction Zone+May 9 2011, 09:37 PM)
synthing, yes we have admitted in real life many times that there would be delays.  But then you could also have a control system that could account for the delay.  The thing is that there is not delay mentioned in  the Russian version and there is no need to put one in the thought problem.  Unimportant  items can  be ignored.  The delay is not important since it would result in a minimal displacement.

Warning: DO NOT READ THIS IF YOU WISH TO MAINTAIN YOUR DELUSIONS! (superfluous warning)

So what happened to all the crowing about stuff happening tomorrow? A non-issue used for rhetorical effect, just as I thought.

Pray tell, what part of "adjust" (i.e. fits, corresponds, or conforms; adapt; accommodate) responding to "monitors" (i.e. observe, record, or detect (an operation or condition) with instruments that have no effect upon the operation or condition) accounts for no delay? Between monitors and adjusts is an EXPLICIT (means clearly stated) delay.

So which is it, no delay or the delay can be ignored? Make up your mind. Either stay true to the Russian wording or ignore the delay.

ANY displacement is important as it is cumulative.
Sithdarth
QUOTE
You're a real joke, darth. So your "magic force" suddenly disappears if the plane is all of a sudden a car instead?

Nope, thank you for proving that you are not even paying attention.

QUOTE (->
 QUOTE You're a real joke, darth. So your "magic force" suddenly disappears if the plane is all of a sudden a car instead?

Nope, thank you for proving that you are not even paying attention.

Ha ha. And, to boot, now you're an expert in the Russian language telling us about all the "alternative translations".

Nope, but I have seen other translations and I do know that translating from any language introduces ambiguity.

QUOTE
One wonders how the Russians themselves ever did any engineering with such a sloppy, ambiguous language.

The original is probably a lot less ambiguous than the translation given the limitations of translating anything.

QUOTE (->
 QUOTE One wonders how the Russians themselves ever did any engineering with such a sloppy, ambiguous language.

The original is probably a lot less ambiguous than the translation given the limitations of translating anything.

Still waiting for your "design" that predicts what the future speed of the wheel is going to be.

Are you really this dense? You measure the wheel speed at say 5 to 10 points. Plot this as a function of time. Take the derivative to figure out the angular acceleration. Viola you know the speed of the wheel in the future.

QUOTE
And, remember, since you have told us that you have personally designed numerous control systems, I'm sure you'll have no trouble outlining it in sufficient detail that we can verify it ...

I never said numerous. I also never said they were physical systems. The system itself is actually pretty much all programing. You take data from the wheel in terms of wheel speed which I'm sure you are smart enough to figure out for yourself and then you apply the process described above.

QUOTE (->
 QUOTE And, remember, since you have told us that you have personally designed numerous control systems, I'm sure you'll have no trouble outlining it in sufficient detail that we can verify it ...

I never said numerous. I also never said they were physical systems. The system itself is actually pretty much all programing. You take data from the wheel in terms of wheel speed which I'm sure you are smart enough to figure out for yourself and then you apply the process described above.

Did your little friend SD not say "It has been demonstrated many times how an accelerating belt will apply a transverse force to an object rolling without slipping."?

Are not the idler wheels "rolling without slipping"? So, where is the transverse force? Why isn't it pushing the cart backwards?

Did you not even bother to read?

Belt pushes on tire, tire pushes on axle, axle pushes on frame. At the same time tire pushes on belt, belt pushes on its supporting axle, that axle also pushes on frame. End result no net force. It is that simple.

------------------------------------------------------------------------------------------
QUOTE
That was the whole point of my example system on a frictionless floor, Sithdarth. Please note Dabeer's answer where he points out that if the wheels were on a plane that did thrust them horizontally, then the belt system would move and the plane would take off.

That was never said.

QUOTE (->
 QUOTE That was the whole point of my example system on a frictionless floor, Sithdarth. Please note Dabeer's answer where he points out that if the wheels were on a plane that did thrust them horizontally, then the belt system would move and the plane would take off.

That was never said.

This should tell you that the magnitude of any retarding force on the plane from the belt via the lane wheels is not as great as you claim.

Prove this mathematically or stop saying it.

QUOTE
And in the castor 'ring' examle, this is even more true.

In no way addresses any of the points I raised. Either offer counter arguments or leave as you are not participating in the argument.

QUOTE (->
 QUOTE And in the castor 'ring' examle, this is even more true.

In no way addresses any of the points I raised. Either offer counter arguments or leave as you are not participating in the argument.

And when you say CONDITIONALLY "...if the axle and the centre of mass of the ring accelerates at different rates..." you are merely assuming that rather than demonstrating that condition. Hence your conclusion therefrom is a non-sequitur.

It's called proof by contradiction. Look it up. Basically you assume something is true and then you explore the consequences. If the consequences derived contradict reality, i.e. solid objects passing through each other, then you've proven the assumption is faulty. Ergo I have proven that it is impossible for the axle to move differently than the center of mass of the wheel.

---------------------------------------------------------------------------------------

QUOTE
ANY displacement is important as it is cumulative.

Nope, at least not if you realize nothing about the wording prohibits a predictive system. In which case you can either allow for the delay in the system or ignore since the predictive element can account for it. Of course there was also some discussion of what matching and equals means and there are some alternate translations with the word instant in them.
synthsin75
QUOTE (Sithdarth+May 9 2011, 09:54 PM)
That is only one of the many possible translations from Russian. Some have the word instant in them others don't. Of course there are people here that take the term match or equal quite literally. Which means at ever instant the speeds must be the same. Which means if you insist on a purely reactionary system means the reaction must be instant.

That's an outright lie, as both you and SZ have on countless occasions completely affirmed your claim of following this wording. There are no other translations other than the paraphrasing you use to castrate its actual and clear meaning. Make your mind, either justify using this Russian wording you've advocated the whole time, or present a completely different wording, no longer related to the Russian version.

The term "match" isn't even in there, and is a fabricated argument based on your fabricated paraphrase. Lies supporting lies.
QUOTE
I would ask you what part of this says that the system cannot be predictive? In what way is predicting where something will be in the future and changing a quantity to equal that future value not covered by the definition of adjust? You've changed something so that it fits, corresponds, or conforms to something else. The term adjust does not specify in any way shape or form by what mechanism the adjustment should be achieved. A predictive adjustment is exactly as valid as a reactive adjustment.

Not "adjust", but "monitor AND adjust". Read the definitions again.
QUOTE (->
 QUOTE I would ask you what part of this says that the system cannot be predictive? In what way is predicting where something will be in the future and changing a quantity to equal that future value not covered by the definition of adjust? You've changed something so that it fits, corresponds, or conforms to something else. The term adjust does not specify in any way shape or form by what mechanism the adjustment should be achieved. A predictive adjustment is exactly as valid as a reactive adjustment.

Not "adjust", but "monitor AND adjust". Read the definitions again.
You do realize all choices of interpretation of the wording are equally arbitrary. Well except for those translations with the word instant. But either way there interpretations in which the results described in the wording can be obtained and for the sake of argument it is generally better to go with the option that can be discussed over the option where no discussion is possible.

Of course you'd say that interpretations are arbitrary, as yours is the most. Arbitrarily adding instantaneous reaction and justifying this by claiming the question to be a pure thought problem, which in turn doesn't allow such assumptions. You're just full of rhetorical nonsense and circular argument.
QUOTE
No such thing has come remotely close to happening. The only thing that is happened is people complaining about me being arbitrary and biased while being equally arbitrary and biased and refusing to acknowledge that they are being arbitrary and biased.

More circular rhetoric unsupported. You erode the grounds of your own argument in a vain attempt to erode your opposition.
QUOTE (->
 QUOTE No such thing has come remotely close to happening. The only thing that is happened is people complaining about me being arbitrary and biased while being equally arbitrary and biased and refusing to acknowledge that they are being arbitrary and biased.

More circular rhetoric unsupported. You erode the grounds of your own argument in a vain attempt to erode your opposition.
It isn't. However it is the only one that allows any discussion to occur and therefore for the sake of argument its the one we should be focused on. At the very least it prevents anyone from saying this is impossible because there is one way that it is possible.

It would be infinitely better to just state a new and clear question that doesn't rely on any nonsense interpretations of your touted Russian version.
QUOTE
How exactly?

What is monitored? Wheel speed. What is adjusted to? Wheel speed. Of course this is exactly why your bias favors a pure thought problem, so that you can avoid the introduction of predictive error that the ACTUAL wording seems to account for. So your instantaneous engineering consideration only exists to replace something the wording already handles.
QUOTE (->
 QUOTE How exactly?

What is monitored? Wheel speed. What is adjusted to? Wheel speed. Of course this is exactly why your bias favors a pure thought problem, so that you can avoid the introduction of predictive error that the ACTUAL wording seems to account for. So your instantaneous engineering consideration only exists to replace something the wording already handles.
It isn't an addition it is a difference of interpretation. Something you seem unable to understand just like you can't understand how all your arguments about this point are based in equally arbitrary and biased reasoning.

Definitions, which you don't seem to be able to equally resort to. You have to jump through convoluted hoops about minimal engineering considerations, pure thought problems (which forbid further engineering considerations), fabricated paraphrases, etc.
QUOTE
I am doing neither. No place in the wording is a predictive system prohibited. You simply cannot admit to being wrong and so you attempt to force your interpretation as the only one possible when it isn't. I simply put mine forward for the sake of argument because it is the only why to actually have a discussion on the topic.

Repeating yourself.
QUOTE (->
 QUOTE I am doing neither. No place in the wording is a predictive system prohibited. You simply cannot admit to being wrong and so you attempt to force your interpretation as the only one possible when it isn't. I simply put mine forward for the sake of argument because it is the only why to actually have a discussion on the topic.

Repeating yourself.
Prove it.

You're the one who insists that a pure thought problem not include engineering considerations. So that's between you and your other personality.
QUOTE
I totally did the latter. You simply refuse to see it because of your bias.

You're totally either a liar or self-deluded.
QUOTE (->
 QUOTE I totally did the latter. You simply refuse to see it because of your bias.

You're totally either a liar or self-deluded.
You really know that little about math? What are you even doing here?

Anyway the point is that if you want to state that a summation of infinitesimal quantities equals something other than zero you have to prove that it does. You can't simply assume that it does equal something other than zero. Generally speaking infinitesimal summations add to finite values as well. So that not only do you have to prove the summation is not zero you also have to prove that it is infinite.

All this means that any argument involving the addition of a series of infinitesimal displacements and how that effects the plane's motion requires a mathematical proof that said infinitesimals actually sum to a finite value.

You're the one who wants to use infinitesimals to justify an instantaneous reaction. The onus is on you to show how what you introduced applies. Not on me to prove the opposite of what you introduce. That is the default troll/crank tactic to put the onus of their assertions upon any opposition. Make your own argument.
QUOTE
Nope, at least not if you realize nothing about the wording prohibits a predictive system. In which case you can either allow for the delay in the system or ignore since the predictive element can account for it. Of course there was also some discussion of what matching and equals means and there are some alternate translations with the word instant in them.

Fabricated translations.
Sithdarth
QUOTE
That's an outright lie, as both you and SZ have on countless occasions completely affirmed your claim of following this wording. There are no other translations other than the paraphrasing you use to castrate its actual and clear meaning. Make your mind, either justify using this Russian wording you've advocated the whole time, or present a completely different wording, no longer related to the Russian version.

Prove it.

QUOTE (->
 QUOTE That's an outright lie, as both you and SZ have on countless occasions completely affirmed your claim of following this wording. There are no other translations other than the paraphrasing you use to castrate its actual and clear meaning. Make your mind, either justify using this Russian wording you've advocated the whole time, or present a completely different wording, no longer related to the Russian version.

Prove it.

The term "match" isn't even in there, and is a fabricated argument based on your fabricated paraphrase. Lies supporting lies.

It was in a previous version mentioned on these very forums as a translation.

QUOTE
Not "adjust", but "monitor AND adjust". Read the definitions again.

There is nothing in monitor that prevents a predictive system. In order to predict I system I first must monitor it and then I can adjust it based on the prediction I get from monitoring. You have failed to in anyway prove that a predictive system is inconsistent with the wording.

Specifically a predictive system does nothing to interfere with the ability to detect, observe, or record an operation or condition with instruments. Nor are the instruments that are doing the recording effecting the the operation or condition they are recording. Thus a predictive system is still perfectly within the bounds of the definitions of monitoring and adjusting.

QUOTE (->
 QUOTE Not "adjust", but "monitor AND adjust". Read the definitions again.

There is nothing in monitor that prevents a predictive system. In order to predict I system I first must monitor it and then I can adjust it based on the prediction I get from monitoring. You have failed to in anyway prove that a predictive system is inconsistent with the wording.

Specifically a predictive system does nothing to interfere with the ability to detect, observe, or record an operation or condition with instruments. Nor are the instruments that are doing the recording effecting the the operation or condition they are recording. Thus a predictive system is still perfectly within the bounds of the definitions of monitoring and adjusting.

Of course you'd say that interpretations are arbitrary, as yours is the most.

Prove it. Also generally speaking things are more arbitrary than other things. Or rather there is no point in calling something more arbitrary than something else.

QUOTE
Arbitrarily adding instantaneous reaction and justifying this by claiming the question to be a pure thought problem, which in turn doesn't allow such assumptions.

Prove it.

QUOTE (->
 QUOTE Arbitrarily adding instantaneous reaction and justifying this by claiming the question to be a pure thought problem, which in turn doesn't allow such assumptions.

Prove it.

You're just full of rhetorical nonsense and circular argument.

Who was it again saying that only their interpretation is the correct one? Certainly wasn't me.

QUOTE
More circular rhetoric unsupported.

This isn't even a sentence.

QUOTE (->
 QUOTE More circular rhetoric unsupported.

This isn't even a sentence.

You erode the grounds of your own argument in a vain attempt to erode your opposition.

Prove it.

QUOTE
It would be infinitely better to just state a new and clear question that doesn't rely on any nonsense interpretations of your touted Russian version.

I could but given how absolutely you are against ever admitting to ever being wrong I see no point.

QUOTE (->
 QUOTE It would be infinitely better to just state a new and clear question that doesn't rely on any nonsense interpretations of your touted Russian version.

I could but given how absolutely you are against ever admitting to ever being wrong I see no point.

What is monitored? Wheel speed. What is adjusted to? Wheel speed. Of course this is exactly why your bias favors a pure thought problem, so that you can avoid the introduction of predictive error that the ACTUAL wording seems to account for. So your instantaneous engineering consideration only exists to replace something the wording already handles.

And nothing at all in that statement actually addresses anything at all. Nor does it in anyway show how the wording forbids a predictive adjustment to some future predicted wheel speed which can be known absolutely to almost any degree of accuracy with very simple equations.

QUOTE
Definitions, which you don't seem to be able to equally resort to. You have to jump through convoluted hoops about minimal engineering considerations, pure thought problems (which forbid further engineering considerations), fabricated paraphrases, etc.

I've quoted definitions to people before. I quoted your definition and demonstrated how they prove my point. I think I resorted to definitions in exactly the same way you did with even better ability since I actually understood the implications of the definitions correctly.

QUOTE (->
 QUOTE Definitions, which you don't seem to be able to equally resort to. You have to jump through convoluted hoops about minimal engineering considerations, pure thought problems (which forbid further engineering considerations), fabricated paraphrases, etc.

I've quoted definitions to people before. I quoted your definition and demonstrated how they prove my point. I think I resorted to definitions in exactly the same way you did with even better ability since I actually understood the implications of the definitions correctly.

Repeating yourself.

So? There is no rule in argumentative debate that says a point can't be repeated.

QUOTE
You're the one who insists that a pure thought problem not include engineering considerations. So that's between you and your other personality.

Don't start this crap again. I've been civil you should stay civil. Otherwise I accept you defeat now on grounds of your inability to form a proper argument.

QUOTE (->
 QUOTE You're the one who insists that a pure thought problem not include engineering considerations. So that's between you and your other personality.

Don't start this crap again. I've been civil you should stay civil. Otherwise I accept you defeat now on grounds of your inability to form a proper argument.

You're totally either a liar or self-deluded.

Prove it.

QUOTE
You're the one who wants to use infinitesimals to justify an instantaneous reaction. The onus is on you to show how what you introduced applies. Not on me to prove the opposite of what you introduce.

Nope. Beer w/Straw clearly brought them up here:

QUOTE (->
 QUOTE You're the one who wants to use infinitesimals to justify an instantaneous reaction. The onus is on you to show how what you introduced applies. Not on me to prove the opposite of what you introduce.

Nope. Beer w/Straw clearly brought them up here:

I'm talking about the plane moving an infintesimally small distance forward before the reaction of the belt kicks in.

So in essence if previous arguments of the plane not flying were corect, I'm saying "Ya, but if the runway was 1000 billion kilometres long you'd be wrong!"

He brought it up thus he proves it. I have never once (that I remember) ever initiated any discussion on infinitesimal quantities. Sometimes I used the term first but only because someone was using the concept of infinitesimals but not the terminology.

QUOTE
That is the default troll/crank tactic to put the onus of their assertions upon any opposition. Make your own argument.

Then you must be a troll since you are attempting to get me to make an argument raised by someone else.

QUOTE (->
 QUOTE That is the default troll/crank tactic to put the onus of their assertions upon any opposition. Make your own argument.

Then you must be a troll since you are attempting to get me to make an argument raised by someone else.

Fabricated translations.

Prove it. Maybe if you're nice I'll go look some of them up or I think Subduction has them saved somewhere if you ask nicely he might share.
synthsin75
Boring and uninspired dodging.
Sithdarth
QUOTE
*Plane (jet or prop) sits on runway with moving surface (like a conveyor). Surface can move against direction of plane's takeoff. It has a system of control which monitors and adjusts the speed of surface's motion in such a way that speed of rotation of the wheels of the plane is equal to the speed of motion of the surface. Question: can the plane accelerate on that surface and take off?

I'm telling you right away: we have half of a street figting over this, involving in discussion two physics teachers and one professor from university. Result that EVERYONE got was different !! Though, the university is of Military Engineering and Communication Wink )
So that not to affect your reasoning, I will not mention positions and weight coefficients of sides of the argument.*

Here is a translation from a native Russian speaker of the earliest known post of any version of plane on a conveyor belt. Of particular note is this section:

QUOTE (->
 QUOTE *Plane (jet or prop) sits on runway with moving surface (like a conveyor). Surface can move against direction of plane's takeoff. It has a system of control which monitors and adjusts the speed of surface's motion in such a way that speed of rotation of the wheels of the plane is equal to the speed of motion of the surface. Question: can the plane accelerate on that surface and take off?I'm telling you right away: we have half of a street figting over this, involving in discussion two physics teachers and one professor from university. Result that EVERYONE got was different !! Though, the university is of Military Engineering and Communication Wink )So that not to affect your reasoning, I will not mention positions and weight coefficients of sides of the argument.*

Here is a translation from a native Russian speaker of the earliest known post of any version of plane on a conveyor belt. Of particular note is this section:

It has a system of control which monitors and adjusts the speed of surface's motion in such a way that speed of rotation of the wheels of the plane is equal to the speed of motion of the surface.

I know it isn't explicitly stated that this situation is maintained at all times (thereby necessitating instantaneous or predictive adjustment) but it is implied by the words equal to. Generally speaking if you mean "equal to" to apply only to a certain time period you specify that time period. Like "the weight of the water displaced is equal to the weight of the object when the object is neutrally buoyant". The lack of a qualifier is usually universally understood to mean the "equal to" condition applies indefinitely. This is something that any scientist or mathematician should understand. If a statement isn't qualified it is automatically assumed to be universal. You have no idea how many points I lost on proves for forgetting qualifying statements.

QUOTE
Boring and uninspired dodging.

Oh so we're describing our own actions now? If you don't have a counter argument man up and admit it.
synthsin75
The statement "speed of rotation of the wheels of the plane is equal to the speed of motion of the surface" IS QUALIFIED by "a system of control which monitors and adjusts". So you forgot yet another qualifying statement.

"Equal to" is limited by "monitors and adjusts". The only reason to include the qualifier "monitors and adjusts" is to explicitly define reactions to be, at a minimum, limited to the speed of light.

ALL physics questions, even thought problems, require the speed of light limit on information, otherwise all causation may be ignored and any analysis is moot. Thus ending up with nonsense about the belt initiating wheel rotation.

IF this is considered a pure thought problem, NO engineering considerations, including instantaneous reactions, may be included. The speed of light limit is a physics, not engineering, consideration.

IF this is considered a simple and trivial riddle, it would require a complete rewording to constitute a proper thought problem. But it doesn't require the matching ("equal to") to be a foregone conclusion, unless it is paraphrased to do so.

So there is no other option with this wording but to allow for a delay, without predictive reaction. The only logical necessity for monitoring is an inherently or assumed unacceptable unpredictability.

You just affirmed the Russian version (same as I quoted) yet again, proving the point that you fabricated any translation, other than your arbitrary paraphrase, that included instantaneous reaction. Nor is "match" in there. You have repeatedly admitted that instantaneous reaction is by no means explicitly stated, and thereby affirming the arbitrary nature of your own paraphrasing.

I've already clearly shown that you contradict yourself by requiring no engineering considerations for a pure thought problem while insisting on an instantaneous reaction, which you've already admitted to being an engineering consideration. Evidence of either dishonesty or hypocrisy.

You claim arbitrary interpretations in an attempt to undermine opposing and direct meaning, only to disguise your own. You refuse to make a clear statement of the thought problem you wish to examine, with only an accusation of opposing character. No grounds at all.

You demonstrated nothing with the definitions provided you. You ignore that something has to first exist to be observed, only then to be a basis for adjustment. The Russian version clearly accounts for any unpredictable variance of thrust acceleration, but only by means of a reasonable delay. Only a new problem statement can avoid this.

It cannot be helped if you contradict yourself by forbidding what you introduce, i.e. engineering consideration of instantaneous reaction. That give a clear impression of being of two minds on a single point, which is the definition of confusion.

It is abundantly clear that such assertions are deceptive, whether internally or externally, which cannot be determined.

Instantaneous reaction, introduced by you, requires limits, which introduce infinitesimals.
NoCleverName
You're still a joke, Darth. Let's put the engine that drives the belt on a rear-wheel drive car. No need for a moving belt, here. So now the car takes off using the same acceleration profile as it would if the engine was instead driving a belt that is to hold back a plane. So now the front wheels encounter an accelerating, moving surface ... hey, it could have been a moving belt you know? But these front wheels are "opposed" by the same force that WOULD have been used to stop the plane ... they really can't tell the difference between being pushed over the surface or having the surface dragged under them, can they ("frames of reference", Zone)?

So why doesn't the car just sit there unmoving? The forward force is exactly countered by the opposing force ...according to you.
NoCleverName
QUOTE (synthsin75+May 10 2011, 03:33 AM)
Instantaneous reaction, introduced by you, requires limits, which introduce infinitesimals.

I should point out that he needs "instantaneous reaction" AND "predictive action" because as constituted his theory would be unable to slow the plane one iota. The plane is delivering its thrust continuously while the belt system, if just instantaneous and limited to simply "matching" the wheel speed, does so over a much shorter time. Thus, the "impulse" (force * time) of the plane is much greater than that of the belt. Therefore the plane always gains ground over any period when the system "monitors" before it gets to "adjust". If the plane gets to "lead" then that sets an upper bound on the belt's speed ... otherwise the rules are broken. His theory can't work of the belt is limited to the speed the plane's wheels WOULD HAVE BEEN if unconstrained by a moving belt.

Basically, he needs to bend the rules to allow the wheels to run at any acceleration up to when they'll start to skid. Of course, then comes the huge assumption that all that force is used to counter the plane rather than merely accelerate the wheel ... but we'll let that pass for now.

I love the part where his system is "instantaneous" and "predictive" yet he needs to be able to "plot 5 to 10 points as a function of time" to achieve this "instantaneous" system".
Sithdarth
QUOTE
The statement "speed of rotation of the wheels of the plane is equal to the speed of motion of the surface" IS QUALIFIED by "a system of control which monitors and adjusts". So you forgot yet another qualifying statement.

That is not a qualifier.

qual·i·fi·er (kwl-fr)
n.
1. One that qualifies, especially one that has or fulfills all appropriate qualifications, as for a position, office, or task.
2. Grammar A word or phrase that qualifies, limits, or modifies the meaning of another word or phrase.

monitors and adjust in no way limits or modifies the meaning of equal to. It describes how the equal to condition is achieved and that is all.

QUOTE (->
 QUOTE The statement "speed of rotation of the wheels of the plane is equal to the speed of motion of the surface" IS QUALIFIED by "a system of control which monitors and adjusts". So you forgot yet another qualifying statement.

That is not a qualifier.

qual·i·fi·er (kwl-fr)
n.
1. One that qualifies, especially one that has or fulfills all appropriate qualifications, as for a position, office, or task.
2. Grammar A word or phrase that qualifies, limits, or modifies the meaning of another word or phrase.

monitors and adjust in no way limits or modifies the meaning of equal to. It describes how the equal to condition is achieved and that is all.

"Equal to" is limited by "monitors and adjusts". The only reason to include the qualifier "monitors and adjusts" is to explicitly define reactions to be, at a minimum, limited to the speed of light.

Prove it.

QUOTE
ALL physics questions, even thought problems, require the speed of light limit on information, otherwise all causation may be ignored and any analysis is moot. Thus ending up with nonsense about the belt initiating wheel rotation.

Not really. Newton did everything he did with gravity assuming infinite speed of gravity.

QUOTE (->
 QUOTE ALL physics questions, even thought problems, require the speed of light limit on information, otherwise all causation may be ignored and any analysis is moot. Thus ending up with nonsense about the belt initiating wheel rotation.

Not really. Newton did everything he did with gravity assuming infinite speed of gravity.

IF this is considered a pure thought problem, NO engineering considerations, including instantaneous reactions, may be included. The speed of light limit is a physics, not engineering, consideration.

Instantaneous reactions are purely physics. They are an idealization often used when the time between things is so short it doesn't effect the problem or when the delay between cause in effect can be accounted for in some other way so that it doesn't effect the problem.

QUOTE
IF this is considered a simple and trivial riddle, it would require a complete rewording to constitute a proper thought problem. But it doesn't require the matching ("equal to") to be a foregone conclusion, unless it is paraphrased to do so.

QUOTE (->
 QUOTE IF this is considered a simple and trivial riddle, it would require a complete rewording to constitute a proper thought problem. But it doesn't require the matching ("equal to") to be a foregone conclusion, unless it is paraphrased to do so.

So there is no other option with this wording but to allow for a delay, without predictive reaction. The only logical necessity for monitoring is an inherently or assumed unacceptable unpredictability.

Not even remotely proven.

QUOTE
You just affirmed the Russian version (same as I quoted) yet again, proving the point that you fabricated any translation, other than your arbitrary paraphrase, that included instantaneous reaction. Nor is "match" in there. You have repeatedly admitted that instantaneous reaction is by no means explicitly stated, and thereby affirming the arbitrary nature of your own paraphrasing.

Nice try but nope. Good job not reading a single thing I said though.

QUOTE (->
 QUOTE You just affirmed the Russian version (same as I quoted) yet again, proving the point that you fabricated any translation, other than your arbitrary paraphrase, that included instantaneous reaction. Nor is "match" in there. You have repeatedly admitted that instantaneous reaction is by no means explicitly stated, and thereby affirming the arbitrary nature of your own paraphrasing.

Nice try but nope. Good job not reading a single thing I said though.

I've already clearly shown that you contradict yourself by requiring no engineering considerations for a pure thought problem while insisting on an instantaneous reaction, which you've already admitted to being an engineering consideration. Evidence of either dishonesty or hypocrisy.

1) No you haven't

2) I never said instantaneous reactions are an engineering consideration. I said the exact opposite. Of course you find it impossible to actually argue the points I make so this isn't anything surprising.

QUOTE
You claim arbitrary interpretations in an attempt to undermine opposing and direct meaning, only to disguise your own. You refuse to make a clear statement of the thought problem you wish to examine, with only an accusation of opposing character. No grounds at all.

So essentially your describing exactly what you are doing then? Whose calling people a liar and dishonest? Who started this whole thing about things being arbitrary? Wasn't me.

QUOTE (->
 QUOTE You claim arbitrary interpretations in an attempt to undermine opposing and direct meaning, only to disguise your own. You refuse to make a clear statement of the thought problem you wish to examine, with only an accusation of opposing character. No grounds at all.

So essentially your describing exactly what you are doing then? Whose calling people a liar and dishonest? Who started this whole thing about things being arbitrary? Wasn't me.

You demonstrated nothing with the definitions provided you. You ignore that something has to first exist to be observed, only then to be a basis for adjustment. The Russian version clearly accounts for any unpredictable variance of thrust acceleration, but only by means of a reasonable delay. Only a new problem statement can avoid this.

And yet the presence of a delay in no way keeps you from using a predictive system. Also, you failed to prove that the wording even requires a delay in a pure thought experiment.

QUOTE
It cannot be helped if you contradict yourself by forbidding what you introduce, i.e. engineering consideration of instantaneous reaction. That give a clear impression of being of two minds on a single point, which is the definition of confusion.

I have not contradicted myself. What I have done is very clearly showed that either way you approach this problem my result is applicable. You can either assume there is no delay, or you can build a system that functions like there was no delay.

QUOTE (->
 QUOTE It cannot be helped if you contradict yourself by forbidding what you introduce, i.e. engineering consideration of instantaneous reaction. That give a clear impression of being of two minds on a single point, which is the definition of confusion.

I have not contradicted myself. What I have done is very clearly showed that either way you approach this problem my result is applicable. You can either assume there is no delay, or you can build a system that functions like there was no delay.

It is abundantly clear that such assertions are deceptive, whether internally or externally, which cannot be determined.

Nope.

QUOTE
Instantaneous reaction, introduced by you, requires limits, which introduce infinitesimals.

Again you use math you don't understand. Limits don't automatically require an mention of infinitesimals. Also, assuming a non-biased view point it shouldn't even need limits to see that if something happens instantly it happens at the same time as the thing that caused it. Also, I never once tried to say anything about the sum of infinitesimals before it was brought up. It is the sum that requires proof not the use of infinitesimals themselves.
-----------------------------------------------------------------------------

QUOTE (->
 QUOTE Instantaneous reaction, introduced by you, requires limits, which introduce infinitesimals.

Again you use math you don't understand. Limits don't automatically require an mention of infinitesimals. Also, assuming a non-biased view point it shouldn't even need limits to see that if something happens instantly it happens at the same time as the thing that caused it. Also, I never once tried to say anything about the sum of infinitesimals before it was brought up. It is the sum that requires proof not the use of infinitesimals themselves.
-----------------------------------------------------------------------------

You're still a joke, Darth. Let's put the engine that drives the belt on a rear-wheel drive car. No need for a moving belt, here. So now the car takes off using the same acceleration profile as it would if the engine was instead driving a belt that is to hold back a plane. So now the front wheels encounter an accelerating, moving surface ... hey, it could have been a moving belt you know? But these front wheels are "opposed" by the same force that WOULD have been used to stop the plane ... they really can't tell the difference between being pushed over the surface or having the surface dragged under them, can they ("frames of reference", Zone)?

So why doesn't the car just sit there unmoving? The forward force is exactly countered by the opposing force ...according to you.

First off there is a difference between being accelerated over a surface and having a surface accelerate under you. Secondly the plane always moves forward with respect to the belt even when stationary to the observer. This means the observer is moving forward with respect to the belt. So in your example you a measuring the speed of the car from the surface of the "belt" which is obviously wrong. The proper frame would be the one where the car and the observer see the same acceleration of the surface which would make the car stationary. (Or at a constant velocity if the was some mismatch in initial speed) In short you've once again messed up coordinate systems transformations.

QUOTE
I should point out that he needs "instantaneous reaction" AND "predictive action" because as constituted his theory would be unable to slow the plane one iota. The plane is delivering its thrust continuously while the belt system, if just instantaneous and limited to simply "matching" the wheel speed, does so over a much shorter time. Thus, the "impulse" (force * time) of the plane is much greater than that of the belt. Therefore the plane always gains ground over any period when the system "monitors" before it gets to "adjust". If the plane gets to "lead" then that sets an upper bound on the belt's speed ... otherwise the rules are broken. His theory can't work of the belt is limited to the speed the plane's wheels WOULD HAVE BEEN if unconstrained by a moving belt.

Prove it. A constant acceleration provides a constant force and a constant impulse. If the constant acceleration of the belt is high enough to exactly match the thrust of the plane then the plan cannot accelerate.

QUOTE (->
 QUOTE I should point out that he needs "instantaneous reaction" AND "predictive action" because as constituted his theory would be unable to slow the plane one iota. The plane is delivering its thrust continuously while the belt system, if just instantaneous and limited to simply "matching" the wheel speed, does so over a much shorter time. Thus, the "impulse" (force * time) of the plane is much greater than that of the belt. Therefore the plane always gains ground over any period when the system "monitors" before it gets to "adjust". If the plane gets to "lead" then that sets an upper bound on the belt's speed ... otherwise the rules are broken. His theory can't work of the belt is limited to the speed the plane's wheels WOULD HAVE BEEN if unconstrained by a moving belt.

Prove it. A constant acceleration provides a constant force and a constant impulse. If the constant acceleration of the belt is high enough to exactly match the thrust of the plane then the plan cannot accelerate.

Basically, he needs to bend the rules to allow the wheels to run at any acceleration up to when they'll start to skid. Of course, then comes the huge assumption that all that force is used to counter the plane rather than merely accelerate the wheel ... but we'll let that pass for now.

Complete and utter misunderstanding of all the physics that governs this interaction. Heck complete and utter misunderstanding of what makes wheels work.

QUOTE
I love the part where his system is "instantaneous" and "predictive" yet he needs to be able to "plot 5 to 10 points as a function of time" to achieve this "instantaneous" system".

Those things never had anything to do with each other. But good job proving that you have no point and don't bother to even attempt to comprehend the position of the opposition.
NoCleverName
QUOTE (Sithdarth+May 10 2011, 09:24 AM)
First off there is a difference between being accelerated over a surface and having a surface accelerate under you. Secondly the plane always moves forward with respect to the belt even when stationary to the observer. This means the observer is moving forward with respect to the belt. So in your example you a measuring the speed of the car from the surface of the "belt" which is obviously wrong. The proper frame would be the one where the car and the observer see the same acceleration of the surface which would make the car stationary. (Or at a constant velocity if the was some mismatch in initial speed) In short you've once again messed up coordinate systems transformations.

Wrong.
Sithdarth
QUOTE
Wrong.

Prove it. Or to put it another way if I'm sitting still in my car and another car accelerates past me (the other cars velocity is changing not mine) the relative motion is the same as if my car was accelerating backwards past that other car. However, if my car was accelerating backwards inertial forces would be pushing me forwards. Therefore I know I am not accelerating and that the other car is accelerating because I feel no inertial forces. You can always tell if you are accelerating (well except when accelerating at the same rate your frame of reference is accelerating in the opposite direction i.e. free fall). Which is why you can always tell the difference between you accelerating or a surface that is accelerating.

Or perhaps you meant the frame of reference bit. Clearly in the tradition plane on a belt case the surface is accelerating with respect to the 'stationary' observer. Therefore in your example the surface must also be accelerating with what ever you might want to call 'stationary'. Further the motion of the plane is measured with respect to this 'stationary' observer and therefore in your example the motion of the car must also be referenced to this 'stationary' observer. You referenced the velocity of the car to the surface it was moving across which by extension of the analogy represents the belt in the plane on a conveyor belt case. You then proceed to ask why the car isn't stationary with respect to the surface it rolls while the plane is stationary with respect to the surface it rolls on not realizing that the plane is never stationary with respect to the surface it rolls on. The plane is only stationary with respect to a 3rd surface it doesn't interact with that the belt is accelerating relative to. Therefore the car should also be compared to a surface with which the surface it is rolling on is accelerated relative to.
Smulan
From the thread Crop Circles, the following appetizer has several properties in common with some of the posts in this thread. SZ et al, why not head over there and contribute?

QUOTE (Bruce Voigt+ Crop Circles thread)
Oh good it looks like you people will be able to keep up. Allow me to challenge your paradigms.

OK so now we know that within a crop field with no disturbances (air movement etc) the Aura in parts of the field can amalgamate to a packed state. In this state this aura will interact with the Earths force centrifugal.

Our Earth rotates around a meandering force (axis). This created energy secretes from the Earth as a mutating Centrifugal Force.

Forces of equal evolution act upon forces of equal evolution and the Earth's centrifugal force will meld with the likes of smoke or warm air, this all seems gentle and nice BUT.

Earths centrifugal force intermingles with the turmoil of Earth energy and although it is released from the Earth as a force it soon, because of temperature, mutates to interact with air and water.

Energy exits the Earth in a spiral or vortex mutating away from and leaving the centre of the vortex a non-interacting force (calm).

Two examples of vortex size: riding your bike to town you are facing head winds, after a bit of shopping and heading home you are again facing head winds. Imagine standing in the centre (calm) of a small vortex, one step forward the wind hits you from the right, two steps back the wind hits you from the left. Back to centre and stepping left you have the wind in your face and two steps right it hits you from the back. In blustery winds it's the calm vortex centers dancing around leaving the wind to beat you from all directions.
Sithdarth
QUOTE
From the thread Crop Circles, the following appetizer has several properties in common with some of the posts in this thread. SZ et al, why not head over there and contribute?

If you can't tell the difference between that load of crap and proper science I question your ability to even understand science at all.
Smulan
QUOTE (Sithdarth+May 10 2011, 05:33 PM)

If you can't tell the difference between that load of crap and proper science I question your ability to even understand science at all.

Come now, I was referring not to content as such, but rather style of reasoning, consistently underpinned by acknowledged fact and mathematical science, reminiscent of your excellent contributions in this thread.
synthsin75
QUOTE (Sithdarth+May 10 2011, 07:24 AM)

That is not a qualifier.

qual·i·fi·er (kwl-fr)
n.
1. One that qualifies, especially one that has or fulfills all appropriate qualifications, as for a position, office, or task.
2. Grammar A word or phrase that qualifies, limits, or modifies the meaning of another word or phrase.

monitors and adjust in no way limits or modifies the meaning of equal to. It describes how the equal to condition is achieved and that is all.

Exactly, "monitors and adjusts" limits "how the equal to condition is achieved" over time.
QUOTE
Prove it.

Prove monitors and adjusts doesn't require any time, since you are the one making assertions you admit are not explicit in the question, and the onus thus falls on you. Anyone else can clearly see that "monitors and adjusts" limits "how the equal to condition is achieved" over time.

"Monitor and adjusts" modifies something. What else could it modify, if not delay? If this is intended as a thought problem, which you've repeatedly affirmed, all wording is intentional and meaningful.
QUOTE (->
 QUOTE Prove it.

Prove monitors and adjusts doesn't require any time, since you are the one making assertions you admit are not explicit in the question, and the onus thus falls on you. Anyone else can clearly see that "monitors and adjusts" limits "how the equal to condition is achieved" over time.

"Monitor and adjusts" modifies something. What else could it modify, if not delay? If this is intended as a thought problem, which you've repeatedly affirmed, all wording is intentional and meaningful.
Not really. Newton did everything he did with gravity assuming infinite speed of gravity.

Complete straw man. Even if gravity was dynamic enough locally for its change to effect interactions, you know damn well he wouldn't have had to means to measure it, as we couldn't even directly measure it until 2002. Any fundamental physics, such as the invariant speed of light, is included in any reasonable though problem, once known.
QUOTE
Instantaneous reactions are purely physics. They are an idealization often used when the time between things is so short it doesn't effect the problem or when the delay between cause in effect can be accounted for in some other way so that it doesn't effect the problem.

Neither of which you have shown, which is your motivation for introducing the engineering consideration of a predictive reaction. So prove that the time of reaction is completely negligible. And if that proof requires limits or infinitesimals, you must also prove how these do not sum to a finite value. These are all your assertions and introductions.
QUOTE (->
 QUOTE Instantaneous reactions are purely physics. They are an idealization often used when the time between things is so short it doesn't effect the problem or when the delay between cause in effect can be accounted for in some other way so that it doesn't effect the problem.

Neither of which you have shown, which is your motivation for introducing the engineering consideration of a predictive reaction. So prove that the time of reaction is completely negligible. And if that proof requires limits or infinitesimals, you must also prove how these do not sum to a finite value. These are all your assertions and introductions.
QUOTE (me+)
IF this is considered a simple and trivial riddle, it would require a complete rewording to constitute a proper thought problem. But it doesn't require the matching ("equal to") to be a foregone conclusion, unless it is paraphrased to do so.

You and SZ are the only ones who introduced the self-serving paraphrasing that stated matching without any qualifying statement of time. It is this paraphrase that is trivial.
QUOTE
Not even remotely proven.

The onus is not on me to prove what the question clearly states, but on you to prove what you repeatedly admit the question doesn't explicitly state, as far as no delay goes.
QUOTE (->
 QUOTE Not even remotely proven.

The onus is not on me to prove what the question clearly states, but on you to prove what you repeatedly admit the question doesn't explicitly state, as far as no delay goes.
QUOTE (me+)

You just affirmed the Russian version (same as I quoted) yet again, proving the point that you fabricated any translation, other than your arbitrary paraphrase, that included instantaneous reaction. Nor is "match" in there. You have repeatedly admitted that instantaneous reaction is by no means explicitly stated, and thereby affirming the arbitrary nature of your own paraphrasing.

Nice try but nope. Good job not reading a single thing I said though.

You have yet to show any proof otherwise, while I have quoted you to affirm what I say. So this is just another unsupported dodge.
QUOTE
1) No you haven't

2) I never said instantaneous reactions are an engineering consideration. I said the exact opposite. Of course you find it impossible to actually argue the points I make so this isn't anything surprising.

The only reason to introduce a predictive reaction (engineering, as you've affirmed) is to justify an assumption of instantaneous reaction. And this is the ONLY way you can justify an instantaneous reaction within the explicit wording of the question (which you've also admitted). So, justifying convolutions aside, the instantaneous requires engineering considerations.
QUOTE (->
 QUOTE 1) No you haven't2) I never said instantaneous reactions are an engineering consideration. I said the exact opposite. Of course you find it impossible to actually argue the points I make so this isn't anything surprising.

The only reason to introduce a predictive reaction (engineering, as you've affirmed) is to justify an assumption of instantaneous reaction. And this is the ONLY way you can justify an instantaneous reaction within the explicit wording of the question (which you've also admitted). So, justifying convolutions aside, the instantaneous requires engineering considerations.
So essentially your describing exactly what you are doing then? Whose calling people a liar and dishonest? Who started this whole thing about things being arbitrary? Wasn't me.

You've already admitted your interpretation was arbitrary, no doubt in an attempt to seem honest. I don't make the foolish mistake of eroding the grounds for my own point, mostly because I don't need to justify my honesty.
QUOTE
And yet the presence of a delay in no way keeps you from using a predictive system. Also, you failed to prove that the wording even requires a delay in a pure thought experiment.

The proof will always fail solely upon your poor comprehension. You admittedly choose to ignore explicit statements in the question, and cannot fault me for refusing to do so. And you've already and repeatedly dismissed engineering considerations, so you cannot introduce one to justify your instantaneous reaction.
QUOTE (->
 QUOTE And yet the presence of a delay in no way keeps you from using a predictive system. Also, you failed to prove that the wording even requires a delay in a pure thought experiment.

The proof will always fail solely upon your poor comprehension. You admittedly choose to ignore explicit statements in the question, and cannot fault me for refusing to do so. And you've already and repeatedly dismissed engineering considerations, so you cannot introduce one to justify your instantaneous reaction.
I have not contradicted myself. What I have done is very clearly showed that either way you approach this problem my result is applicable. You can either assume there is no delay, or you can build a system that functions like there was no delay.

Yes, you have. You have clearly admitted that you must ignore explicit wording to assume instantaneous reaction, and then only introduce your admitted predictive engineering consideration to justify doing so.

QUOTE
QUOTE (->
 QUOTE How is predictive reaction specified in the Russian wording you so tout? It's not specified exactly but then again the Russian wording is pure thought problem where things can happen instantly and where we don't worry about any delay.

Proof.
QUOTE
Again you use math you don't understand. Limits don't automatically require an mention of infinitesimals. Also, assuming a non-biased view point it shouldn't even need limits to see that if something happens instantly it happens at the same time as the thing that caused it. Also, I never once tried to say anything about the sum of infinitesimals before it was brought up. It is the sum that requires proof not the use of infinitesimals themselves.

Pedantic nonsense. They don't require a "mention of infinitesimals", for the very good reason that limits were originally formulated on infinitesimals, as in calculus or analysis. So you claim your unsupported instantaneity means you don't have to address it. Nice, just ignore explicitly showing the instantaneity so you never have to justify it.
NoCleverName
QUOTE (Sithdarth+May 10 2011, 01:17 PM)
Which is why you can always tell the difference between you accelerating or a surface that is accelerating.

Oh, so THAT'S how you get around the little detail of "for every force, there is an equal opposing force" in your little world?
Sithdarth
QUOTE
Oh, so THAT'S how you get around the little detail of "for every force, there is an equal opposing force" in your little world?

Nope because I don't need to get around that fact. I in fact use that fact.

------------------------------------------------------

QUOTE (->
 QUOTE Oh, so THAT'S how you get around the little detail of "for every force, there is an equal opposing force" in your little world?

Nope because I don't need to get around that fact. I in fact use that fact.

------------------------------------------------------

Exactly, "monitors and adjusts" limits "how the equal to condition is achieved" over time.

No it doesn't. There is not one part of either monitors or adjusts the in anyway limits the temporal nature of the equaling.

QUOTE
Prove monitors and adjusts doesn't require any time, since you are the one making assertions you admit are not explicit in the question, and the onus thus falls on you. Anyone else can clearly see that "monitors and adjusts" limits "how the equal to condition is achieved" over time.

Wrong. You made the assertion that monitors and adjusts limits the temporal equaling you prove it.

QUOTE (->
 QUOTE Prove monitors and adjusts doesn't require any time, since you are the one making assertions you admit are not explicit in the question, and the onus thus falls on you. Anyone else can clearly see that "monitors and adjusts" limits "how the equal to condition is achieved" over time.

Wrong. You made the assertion that monitors and adjusts limits the temporal equaling you prove it.

"Monitor and adjusts" modifies something. What else could it modify, if not delay?

It modifies nothing. It simply defines the process that is occurring.

QUOTE
Complete straw man. Even if gravity was dynamic enough locally for its change to effect interactions, you know damn well he wouldn't have had to means to measure it, as we couldn't even directly measure it until 2002. Any fundamental physics, such as the invariant speed of light, is included in any reasonable though problem, once known.

Forgetting the motion of the planets around the sun are we?

QUOTE (->
 QUOTE Complete straw man. Even if gravity was dynamic enough locally for its change to effect interactions, you know damn well he wouldn't have had to means to measure it, as we couldn't even directly measure it until 2002. Any fundamental physics, such as the invariant speed of light, is included in any reasonable though problem, once known.

Forgetting the motion of the planets around the sun are we?

Neither of which you have shown, which is your motivation for introducing the engineering consideration of a predictive reaction. So prove that the time of reaction is completely negligible. And if that proof requires limits or infinitesimals, you must also prove how these do not sum to a finite value. These are all your assertions and introductions.

I'm not going to make you case for you.

QUOTE
You and SZ are the only ones who introduced the self-serving paraphrasing that stated matching without any qualifying statement of time. It is this paraphrase that is trivial.

Nope.

QUOTE (->
 QUOTE You and SZ are the only ones who introduced the self-serving paraphrasing that stated matching without any qualifying statement of time. It is this paraphrase that is trivial.

Nope.

The onus is not on me to prove what the question clearly states, but on you to prove what you repeatedly admit the question doesn't explicitly state, as far as no delay goes.

It is entirely on you to prove that your interpretation is in anyway more correct than any other interpretation.

QUOTE
You have yet to show any proof otherwise, while I have quoted you to affirm what I say. So this is just another unsupported dodge.

Except that I did.

QUOTE (->
 QUOTE You have yet to show any proof otherwise, while I have quoted you to affirm what I say. So this is just another unsupported dodge.

Except that I did.

The only reason to introduce a predictive reaction (engineering, as you've affirmed) is to justify an assumption of instantaneous reaction. And this is the ONLY way you can justify an instantaneous reaction within the explicit wording of the question (which you've also admitted). So, justifying convolutions aside, the instantaneous requires engineering considerations.

Already explained why this is wrong.

QUOTE
You've already admitted your interpretation was arbitrary, no doubt in an attempt to seem honest. I don't make the foolish mistake of eroding the grounds for my own point, mostly because I don't need to justify my honesty.

1) You totally do. Your debate tactics are underhanded and very dirty.

2) All interpretations of anything are arbitrary. The fact that you don't understand this goes to the root of your inability to ever consider admitting to being wrong.

3) It doesn't weaken your position to acknowledge the arbitrariness inherent in everything because it is irrelevant. See the "dragon in my garage" argument.

QUOTE (->
 QUOTE You've already admitted your interpretation was arbitrary, no doubt in an attempt to seem honest. I don't make the foolish mistake of eroding the grounds for my own point, mostly because I don't need to justify my honesty.

1) You totally do. Your debate tactics are underhanded and very dirty.

2) All interpretations of anything are arbitrary. The fact that you don't understand this goes to the root of your inability to ever consider admitting to being wrong.

3) It doesn't weaken your position to acknowledge the arbitrariness inherent in everything because it is irrelevant. See the "dragon in my garage" argument.

The proof will always fail solely upon your poor comprehension. You admittedly choose to ignore explicit statements in the question, and cannot fault me for refusing to do so. And you've already and repeatedly dismissed engineering considerations, so you cannot introduce one to justify your instantaneous reaction.

Nothing remotely close to this ever happened.

QUOTE
Yes, you have. You have clearly admitted that you must ignore explicit wording to assume instantaneous reaction, and then only introduce your admitted predictive engineering consideration to justify doing so.

Not a contradiction. Simply a demonstration of the equivalence of two different approaches. Something you are obviously not equipped to understand.

QUOTE (->
 QUOTE Yes, you have. You have clearly admitted that you must ignore explicit wording to assume instantaneous reaction, and then only introduce your admitted predictive engineering consideration to justify doing so.

Not a contradiction. Simply a demonstration of the equivalence of two different approaches. Something you are obviously not equipped to understand.

Proof.

I refer you to the numerical solutions to the 3-body gravitational problem which rely totally on Newtonian mechanics for any two bodies and the sun in our solar system. These are computed assuming instant gravitation action even though it should take as much as 20 minutes or more. They are also quite accurate.

QUOTE
Pedantic nonsense. They don't require a "mention of infinitesimals", for the very good reason that limits were originally formulated on infinitesimals, as in calculus or analysis. So you claim your unsupported instantaneity means you don't have to address it. Nice, just ignore explicitly showing the instantaneity so you never have to justify it.

Nope. Nice try though.

By the way: Mathematical definition of limit. You'll notice it in no way relies on infinitesimals. ε and δ are both real numbers and thus not infinitesimal. You can do limits with the notion of infinitesimals but infinitesimals are not needed to do limits. Another example of you attempting to use something you don't understand.
synthsin75
monitor - to observe, record, or detect (an operation or condition) with instruments that have no effect upon the operation or condition.

To "observe, record, or detect" requires a minimal delay needed for light to traverse from observed to observing person or device. As always, you want to ignore "monitors" as it necessitates a delay. I suppose you assume an observation can be made faster than light? Idiotic.

Yes, I know, you'll say that a thought problem allows for idealizations that directly contradict the explicit wording of a question you insist is already a thought problem, necessitating ignoring none of it. You'll then go on to introduce an engineering predictive reaction to counter it, voiding your own assertion about engineering considerations in thought problems.

You're justification is full of holes. You cannot patch enough to keep that ship from sinking.

If you wish to continue this ridiculous farce that you are abiding by the Russian wording, it is on you to prove how the observation of monitoring doesn't require any time. Everything else is just you dodging about because you know you have no grounds.

--------------------------------------------------------------

Round and round we go on SD's crazy merry-go-round.
Smulan
QUOTE (RealityCheck+May 11 2011, 02:01 AM)
... as EACH of the multiple wheel-periphery rockets reach their LOWERMOST POINT they (and ONLY they, OK?) automatically FIRE, again always in a common horizontal direction ... what will happen (or will not happen, as the case may be) to the whole assembly on that frictionless floor?

If we imagine an unbounded number of rockets with an infinitesimal distance between them, each mounted on an infinitesimal (mathematical) point and firing for an infinitesimal amount of time, the rockets are equivalent to a perfect, non-slipping conveor belt, yielding a purely tangential acceleration.

Naturally, the perfect belt system is as illusive as the perfect rocket system; in reality, both would yield linear movement in the direction of the belt/rockets.
NoCleverName
QUOTE (Sithdarth+May 10 2011, 06:13 PM)
You'll notice it in no way relies on infinitesimals. ε and δ are both real numbers and thus not infinitesimal. You can do limits with the notion of infinitesimals but infinitesimals are not needed to do limits. Another example of you attempting to use something you don't understand.

The fact that you had to look this up and didn't respond with this information "off the top of your head" earlier indicates that YOU YOURSELF didn't know what you were talking about, either. Of course, you now realize that your argument for "instantaneous action" is now blown apart since "instantaneous" doesn't actually exist in limit-based calculus.

Oh, and I can mention "off the top of my head" that only recently was calculus "re-proven" using infinitesimals. It had existed quite nicely on somewhat shaky ground of limits for several hundred years. But since infinitesimals aren't real (or even complex) numbers don't think that brings back "instantaneous".

I'm still yukking it up over your insistence that there are different forces created when pushing a wheel over an unmoving belt versus pulling a belt under a wheel.
Sithdarth
QUOTE
The fact that you had to look this up and didn't respond with this information "off the top of your head" earlier indicates that YOU YOURSELF didn't know what you were talking about, either.

Not even remotely.

QUOTE (->
 QUOTE The fact that you had to look this up and didn't respond with this information "off the top of your head" earlier indicates that YOU YOURSELF didn't know what you were talking about, either.

Not even remotely.

Of course, you now realize that your argument for "instantaneous action" is now blown apart since "instantaneous" doesn't actually exist in limit-based calculus.

Oh you are so very very wrong. Go look up how instantaneous velocities are defined.

QUOTE
Oh, and I can mention "off the top of my head" that only recently was calculus "re-proven" using infinitesimals. It had existed quite nicely on somewhat shaky ground of limits for several hundred years. But since infinitesimals aren't real (or even complex) numbers don't think that brings back "instantaneous".

What you can and can't mention of the top of your head is irrelevant. Also you can't prove this as off the top of your head anyway. So this just looks like a pathetic attempt to seem smart. This is something you could have easily picked up from the Wiki on infinitesimals.

QUOTE (->
 QUOTE Oh, and I can mention "off the top of my head" that only recently was calculus "re-proven" using infinitesimals. It had existed quite nicely on somewhat shaky ground of limits for several hundred years. But since infinitesimals aren't real (or even complex) numbers don't think that brings back "instantaneous".

What you can and can't mention of the top of your head is irrelevant. Also you can't prove this as off the top of your head anyway. So this just looks like a pathetic attempt to seem smart. This is something you could have easily picked up from the Wiki on infinitesimals.

I'm still yukking it up over your insistence that there are different forces created when pushing a wheel over an unmoving belt versus pulling a belt under a wheel.

Never said anything of the sort. You really need to work on the lying thing.

------------------------------------------------------

Reality Check I don't have time for a full explanation but I will tell you the system does move forward. The difference being that if we assume the force it applies is constant the overall acceleration decreases since the rocket even in your system isn't 100% horizontal the whole time and it is working against the moment of inertia of the wheel as well as the inertia of the frame.
NoCleverName
QUOTE (Sithdarth+May 11 2011, 10:14 AM)
Oh you are so very very wrong. Go look up how instantaneous velocities are defined.

So now you are claiming infinitesimals DO exist in the real numbers?
Sithdarth
QUOTE
So now you are claiming infinitesimals DO exist in the real numbers?

Nope. But that in no way prevents instantaneous things. Just because the width of a single point is not a real number doesn't mean the position of the point isn't a real number. It also doesn't mean that you can't do math in the real numbers with the properties of that point including the value and the slope at that point (which is just the tangent line which is easily defined without the use of infinitesimals). The only thing infinitesimals do in calculus is make the reasoning easier to understand. You can do absolutely everything there is to do in calculus without ever using infinitesimals. Which is actually what you do in a Real Analysis course. The trick is that it's a lot harder to understand conceptually. If you tried to teach it to beginning math students they would probably implode.

There is a heck of a lot more to math, and especially calculus, than most people ever learn.
NoCleverName
QUOTE (Sithdarth+May 11 2011, 12:21 PM)
Just because the width of a single point is not a real number doesn't mean the position of the point isn't a real number.

Just for future reference: points are dimensionless ... a better way of describing them than "undefined width".

However, you are better off than most people in that you understand that a "real number" is a location on the number line and what most typically call a "number" (that string of symbols composed of digits) is merely the label or "address" of the actual real number. That is an important understanding and you are well off to have it.

As far as tangents go, I am reminded of a previous argumentative poster, a certain "StevenA", who claimed that a specific, certain, and definitive "tangent" was impossible because a line was defined by TWO points and the tangent (supposedly) passed through just one. So, he thought there were two possibilities: either the tangent was multivalued (depending on which two "adjacent" points you used to define it) or points really weren't all that distinct.Therefore, I think he believed, it was possible to have neighboring points that somehow "touched" and shared some of the same location. It was these two points that actually defined the tangent. Of course, this was all bound up in one of those 0.9999... = 1 discussions (second only to plane-on-a-conveyor for length and heat).

Sithdarth
QUOTE
After you have done that I will point out the absurdity of your claims by describing a further means of propulsion which your 'concept' would 'in theory' have made possible but which has been already proved to be ineffective in reality.

Yeah that isn't going to happen. You know why that isn't going to happen? Because of this:

QUOTE (->
 QUOTE After you have done that I will point out the absurdity of your claims by describing a further means of propulsion which your 'concept' would 'in theory' have made possible but which has been already proved to be ineffective in reality.

Yeah that isn't going to happen. You know why that isn't going to happen? Because of this:

You DO realise that in the freewheeling case the only rotational inertia comes from the wheel ONLY and NOT the whole assembly, don't you? Only in the 'brake-frozen' fixed wheel case will the whole assembly rotational inertia come into play....and that any tendency for the whole assembly to rotate will be transmitted to the FLOOR as a NORMAL/PERPENDICULAR force on the assembly end which tries to rotate DOWNWARDS. Meaning that. in the FREWWHEELING case, any inertial resistance from the box-frame per se to the tangential rocket/belt force is IMMATERIAL when it comes to HORIZONTAL forces in play.

You can't even comprehend the difference between the fact that the rocket acts to rotate the wheel while simultaneously pushing horizontally, not rotationally, on the frame. A careful rereading of my post will reveal that I made a very clear distinction between the rotational moment of inertia of just the wheel and the plain old inertia of the assembly. The rocket acts on both at the same time.

QUOTE
See? In free space, the only inertia resisting the rocket/belt tangential acceleration would be the minuscule wheel-mass inertia. No axle involved, and even a hole where the axle would normally be. And yet that minuscule inertial resistance to tangential acceleration causes rotation IN SITU only, INSTEAD of the wheel in free space flying off linearly. Which means that hardly any inertia still is capable of causing rotation EASILY even in the absence of box-frame/plane mass/inertia.

Absolutely wrong. Oh and by the way remember this:

QUOTE (->
 QUOTE See? In free space, the only inertia resisting the rocket/belt tangential acceleration would be the minuscule wheel-mass inertia. No axle involved, and even a hole where the axle would normally be. And yet that minuscule inertial resistance to tangential acceleration causes rotation IN SITU only, INSTEAD of the wheel in free space flying off linearly. Which means that hardly any inertia still is capable of causing rotation EASILY even in the absence of box-frame/plane mass/inertia.

Absolutely wrong. Oh and by the way remember this:

Only a full explanation will do, else you are just handwaving as you accuse others of doing.

If I can't hand wave than you can't hand wave. So either stop talking until you can do the math and present proof or don't complain when I do it.

QUOTE
So please explain everything, especially about how a fixed wheel that transmits the whole reaction/belt force HORIZONTALLY to the assembly is then equivalent to a freewheeling wheel that can only transmit a ROTATIONAL reaction/force resisted ONLY by the freewheeling wheels own ROTATIONAL inertia SEPARATED by a frictionless hub from the NORMAL/perpendicular resistance to rotation that would otherwise come from the FLOOR-to-box-frame contact ONLY if/when the wheel is essentially 'brake-on' fixed to the frame.

I've done this several times and every time you simply refuse to listen, don't in any way address it with a counter argument, and then repeat the same wrong statements. I'd tell you to go find a physics professor but I don't want to inflict you on some unsuspecting stranger.

synthsin75
"Observe" the sound of crickets.
Sithdarth
QUOTE
The linear movement you allude to is not evident when the 'freewheeling' case is run, else rockets on spaceships would merely be mounted on freewheeling wheel structures on the side of the ship and STILL go 'forward' instead of the wheels just going round and round on their mountings on the side of the spaceship.

No they wouldn't. Also that isn't a justification for your assertion anyways. It doesn't constitute proof that what you say is true primarily because there are many other factors in play. In fact if what you say was true no one would bother to but maneuvering thrusters on both sides of space craft to save weight. However they do for several reasons not the least of which is that having them only on one side would result in both rotations and translations at the same time.

QUOTE (->
 QUOTE The linear movement you allude to is not evident when the 'freewheeling' case is run, else rockets on spaceships would merely be mounted on freewheeling wheel structures on the side of the ship and STILL go 'forward' instead of the wheels just going round and round on their mountings on the side of the spaceship.

No they wouldn't. Also that isn't a justification for your assertion anyways. It doesn't constitute proof that what you say is true primarily because there are many other factors in play. In fact if what you say was true no one would bother to but maneuvering thrusters on both sides of space craft to save weight. However they do for several reasons not the least of which is that having them only on one side would result in both rotations and translations at the same time.

No. It is you who are making the claims. I merely point to examples which highlight the non-sequiturs in your claims. Now it is your obligation to fully explain away those examples instead of handwaving. Also, it is quite clear that I do understand, as I make clear in the very next bit you quoted, as follows...

We are both making claims and we both have to prove them. Simply stating something that supposedly counters an argument made is not enough. The statement must be proven and if I can't use hand waving to do so neither can you.

QUOTE
Note where I clearly said TANGENTIAL acceleration (ie, meaning horizontal at the lowest point where rocket/belt contact point is during force transfer). OK? Can you stop the evasion semantics and start explaining yourself?

I did no such thing and that statement is wrong for many many reasons. The primary one being that forces are perfectly capable of doing more than one thing. Another being that the tangential force gets transmitted to the axle just fine. Otherwise cars wouldn't be able to move.

QUOTE (->
 QUOTE Note where I clearly said TANGENTIAL acceleration (ie, meaning horizontal at the lowest point where rocket/belt contact point is during force transfer). OK? Can you stop the evasion semantics and start explaining yourself?

I did no such thing and that statement is wrong for many many reasons. The primary one being that forces are perfectly capable of doing more than one thing. Another being that the tangential force gets transmitted to the axle just fine. Otherwise cars wouldn't be able to move.

You are the one who brings in the whole assembly/plane inertia into your handwaving. I merely point to the fact that even in free space the relatively minuscule wheel-only inertia resisting the tangential acceleration is enough to change any tangential HORIZONTAL reaction/force to ROTATIONAL motion WITHOUT ever invoking the frame/plane etc inertia as well.

This is exactly why you are wrong. Forces are not energies. Forces do not get converted from one form to another. Just because a force is producing a torque does not mean that it is not at the same time acting as a linear force.

QUOTE
See? There is no confusion except that you keep mixing inertia/horizontal etc factors from one frame (wheel-rocket/belt) to another (frame/plane-wheel-rocket/belt), and then try to rationalise that non-sequitur away without proving that the two horizontal cases are connected in the way that you think.

No such thing is occurring. The only errors here our yours and they are exactly as stated. That being you have this crazy notion that if a force is producing a torque then the linear effect of the force is reduced which is absolutely not true and patently absurd.

QUOTE (->
 QUOTE See? There is no confusion except that you keep mixing inertia/horizontal etc factors from one frame (wheel-rocket/belt) to another (frame/plane-wheel-rocket/belt), and then try to rationalise that non-sequitur away without proving that the two horizontal cases are connected in the way that you think.

No such thing is occurring. The only errors here our yours and they are exactly as stated. That being you have this crazy notion that if a force is producing a torque then the linear effect of the force is reduced which is absolutely not true and patently absurd.

So please analyse the examples given and do so fully in the light of the obvious difference in horizontal performance of the fixed and free wheel runs. Thanks.

Then stop replying until I have time to actually write a full response. Something I could be doing now if I wasn't dealing with this. Its the last week of classes so I'm slightly busy. Hopefully by Monday I'll have time to fully write something else. It'd be nice if you could be patient until then.
Sithdarth
QUOTE
Oh come on!...no-one said anything about manoeuvering thrusters and you know it. I merely pointed out that if what you contend was true, then, for spaceship 'main drive' rockets, it would make no difference if they were mounted on the sides of the spceship on freewheeling wheel allowed to rotate freely when the rockets are firing.

It clearly would because energy that would otherwise go into moving the ship would be wasted in spinning the wheels. That decrease in efficiency is enough on its own. The fact that you think this demonstrates you have a fundamental deficiency in you understanding of how forces and energies work. Beyond that there are other important reasons. For starters the wheel set up would be more complex making it easier for things to break or go wrong. It would also be heavier and therefore decrease efficiency even more. The increased complexity and amount of material would also increase cost. There would also be a need to create a rather complex control system to make it all work. All these reasons are reasons why no one designing a spaceship would use that method of propulsion. The reason you gave is absolutely not one of them.

You have committed what is known as a Fallacy of the single cause.

Of course this whole line of questioning is an example of a Loaded Question Fallacy. But I'll give you a pass on that one.

QUOTE (->
 QUOTE Oh come on!...no-one said anything about manoeuvering thrusters and you know it. I merely pointed out that if what you contend was true, then, for spaceship 'main drive' rockets, it would make no difference if they were mounted on the sides of the spceship on freewheeling wheel allowed to rotate freely when the rockets are firing.

It clearly would because energy that would otherwise go into moving the ship would be wasted in spinning the wheels. That decrease in efficiency is enough on its own. The fact that you think this demonstrates you have a fundamental deficiency in you understanding of how forces and energies work. Beyond that there are other important reasons. For starters the wheel set up would be more complex making it easier for things to break or go wrong. It would also be heavier and therefore decrease efficiency even more. The increased complexity and amount of material would also increase cost. There would also be a need to create a rather complex control system to make it all work. All these reasons are reasons why no one designing a spaceship would use that method of propulsion. The reason you gave is absolutely not one of them.

You have committed what is known as a Fallacy of the single cause.

Of course this whole line of questioning is an example of a Loaded Question Fallacy. But I'll give you a pass on that one.

And for the car, the tangential force at the wheel ARISES from the CAR causing the wheel to rotate, and NOT the road. The ROTATION force ORIGINATES at the axle/wheel drive system rather than the road!

Doesn't matter. Put the car on a frictionless surface and it can't move. Obviously the tangential force at the road surface is just as important. Yet more evidence of you inability to properly handle forces.

QUOTE
Please stop rationalising and avoiding the issues raised and address the examples given already without further ado.

Ahem:
QUOTE (->
 QUOTE Please stop rationalising and avoiding the issues raised and address the examples given already without further ado.

Ahem:
Then stop replying until I have time to actually write a full response. Something I could be doing now if I wasn't dealing with this. Its the last week of classes so I'm slightly busy. Hopefully by Monday I'll have time to fully write something else. It'd be nice if you could be patient until then.

You want me to focus on the question then stop trying to have the last word and let me focus on the question. Its a simple concept.
synthsin75
Sithdarth, you asked for me to prove how some part of "observe and adjust" requires a delay. I have, and you have suddenly gone silent on this matter. Man up, and admit you were wrong.
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