# Homework Help: Circular motion of a car and curve

1. Oct 16, 2009

### pankti_ptl

A car starts from rest on a curve with a radius of 110 and accelerates at 1.50 . How many revolutions will the car have gone through when the magnitude of its total acceleration is 3.20 ?

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Oct 16, 2009

### rl.bhat

Hi pankti_ptl, welcome to PF.
What are the units of radius and acceleration?
The problems is based on circular motion. What are relevant equation you know about circular motion?

3. Oct 16, 2009

### pankti_ptl

redius in meters and acceleration in m/s^2

4. Oct 16, 2009

### tiny-tim

Welcome to PF!

Hi pankti_ptl! Welcome to PF!

(is the 1.5 a constant tangential acceleration? or is it angular acceleration? )

Just use the same constant acceleration equations as for linear motion, but with θ ω and α instead of s v and a.

5. Oct 16, 2009

### pankti_ptl

it says it is magnitude of total acceleration is 3.20 i dunt kno if its tangental or angular can can we diffrensiate

6. Oct 16, 2009

### pankti_ptl

and for 1.5 it only says acceleration

7. Oct 16, 2009

### tiny-tim

As rl.bhat says, what are the units??

8. Oct 16, 2009

### pankti_ptl

A car starts from rest on a curve with a radius of 110m and accelerates at 1.50m/s^2 . How many revolutions will the car have gone through when the magnitude of its total acceleration is 3.20m/s^2 ?

9. Oct 16, 2009

### tiny-tim

ok, so the units are m/s2.

And if the car is constrained to follow a circle (a curve of fixed radius), then this is the tangential acceleration.

So convert 1.5 m/s2 into angular acceleration (α), and then use the standard constant acceleration equations, for θ ω and α.