Here is the question, At the instant the traffic light turns green, a car that has been waiting at an intersection starts forward with a constant acceleration of 3.20m/s^2. At the same instant, a truck witha constant speed of 20.0m/s overtakes the car.

question: Hot far beyond it's starting point does the car overtake the truck?

I think I need to write an equation for x , for both the car and the truck. and then set them equal to each other...

Car is x= (1.60m/s^2) * t^2

Truck is x= 20.0m/s * t

One I have the equation set up how to I slove for distance?

Thanks!

Two equations, two unknowns, solve it however you know how to solve simultaneous equations.

Solve for t first. After you find t, plug it into either one of the equations you have for distance and you'll have the answer.

Car is x= (1.60m/s^2) * t^2

Truck is x= 20.0m/s * t

20*t=(1.6^2)*t*t
20=(1.6^2)*t
...
...
...

then take your t and plug it into x=20*t.