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yuna4034
8th March 2012 - 10:01 PM
I am stuck in this problem.

A proton has a mass of 1.672 x 10^-27 kg. What is the weight?

I think is 1.638 x 10^-26

But how do I get it?
mathman
8th March 2012 - 10:16 PM
You seem confused as to the definition of weight. It is a measure of the effect of gravity on a mass. On earth a kg. mass is numerically equal to a kg. weight. On the moon the weight would be lower. On the space station the weight would be close to 0.
Robittybob1
8th March 2012 - 10:20 PM
QUOTE (yuna4034+Mar 8 2012, 10:01 PM)
I am stuck in this problem.

A proton has a mass of 1.672 x 10^-27 kg. What is the weight?

I think is 1.638 x 10^-26

But how do I get it?

Would things weigh less on the Moon? Why ? You know it is due to the strength of gravity at the place where you weigh it. So the average strength of gravity on Earth is 9.81 m/sec^2 (acceleration) so that is multiplied by the Mass.
This will give you the weight in Newtons.
rpenner
9th March 2012 - 06:45 AM
mathman -- weight in physics is measured in Newtons, not kilograms.

Multiplying a mass by the standard acceleration due to gravity gives the weight on the surface of the Earth.
mathman
10th March 2012 - 12:57 AM
QUOTE (rpenner+Mar 9 2012, 06:45 AM)
mathman -- weight in physics is measured in Newtons, not kilograms.

Multiplying a mass by the standard acceleration due to gravity gives the weight on the surface of the Earth.

You are formally correct. However in everyday speech when people in Europe weigh themselves they express their weight in kilograms, not newtons.

Similarly in the U.S. pounds are used for both weight and mass in ordinary conversation.
Robittybob1
10th March 2012 - 04:11 AM
QUOTE (mathman+Mar 10 2012, 12:57 AM)
You are formally correct. However in everyday speech when people in Europe weigh themselves they express their weight in kilograms, not newtons.

Similarly in the U.S. pounds are used for both weight and mass in ordinary conversation.

Weighing machines have been calibrated to convert Newtons into Kg or lbs.
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