# Homework Help: Number of Revolutions made

1. Oct 13, 2007

### feedmeister

I had the same question as someone else here, but they figured it out but nothing was said in the post. As such, I was asked to make a new thread..
So, pretty much, I have this question:

1. The problem statement, all variables and given/known data
A car starts from rest on a curve with a radius of 110 m and accelerates at 1.20 m/s^2. How many revolutions will the car have gone through when the magnitude of its total acceleration is 2.20 m/s^2?

2. Relevant equations

theta (final)=theta (initial)+omega*(delta)t+(a*(delta)t^2)/2*r

3. The attempt at a solution

i just have no idea how to figure out the time or the distance (or the angle) it takes the car to get from one acceleration to another...

2. Oct 14, 2007

### BlackWyvern

Total acceleration = vector sum of tangential acceleration and centripetal acceleration.
Solve for centripetal acceleration.

Ac = v^2/r
Solve for v.

Use a kinematic equation with v, you should be done.