# Help with rolling motion

1. Jul 14, 2004

### wilmerena

Hi, Im working on the following problem:

As you drive down the road at 17 m/s you press on the gas pedal and speed up with a uniform acceleration of 1.12m/s2 for 0.65s. If the tires on your car have a radius of 33cm , what is their angular displacement during the period of accceleration?

This is what I did so far,

(1.12m/s^2) / 0.65s = 1.72 m/s acceleration

then 17m/s - 1.72 m/s = 15.28

15.28/.33m = 46 displacement?

Im not sure this was right??

2. Jul 14, 2004

### Galileo

?? The acceleration is 1.12 m/s^2 as you stated in the problem.

You can use the formula for the distance traveled when traveling at constant acceleration.

The distance traveled is

$$d=17(0.65)+1/2(1.12)(0.65)^2=11.3 m$$

If the wheels don`t slip then the distance traveled when the wheels make one revolution is equal to their circumference $$2\pi R$$