# Non-Uniform Circular Motion of car

1. Nov 1, 2007

### 2RIP

A car starts from rest on a curve with a radius of 120m and accelerates at 1.0m/s^2. Through what angle will the car have traveled when the magnitude of its total acceleration is 2.0m/s^2.

This one, I am really lost on how to approach it. I have tangential acceleration at 1.0m/s^2 initially and total final acceleration at 2.0m/s^2. Unless I am interpreting this question incorrectly.

Also another question, does a=r(w^2) only apply to uniform-circular motion or to both uniform and non-uniform?

Thank you in advance!

2. Nov 1, 2007

### PhanthomJay

Total acceleration is the vector sum of the tangential acceleration plus the centripetal acceleration. Centripetal acceleration exists for both uniform and non uniform circular motion; it is just that it is constant for the uniform case and non constant for the latter.

3. Nov 1, 2007

### 2RIP

Yes, but wouldn't tangential acceleration in this question be changing as a function of time? If tangential acceleration were constant, then this is a uniform circular motion.

4. Nov 1, 2007

### PhanthomJay

No, that's not correct. Uniform circular motion implies constant tangential speed, not constant tangential acceleration. Constant tangential acceleration implies a change in tangential speed; hence, motion is non-uniform.

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