# Angular velocity.

1. Dec 9, 2009

### blaze33

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

a wheel rotates with a constant angular acceleration pie rad/s^2. during a certain time interval its angular displacement is pie rad. at the end of the interval its angular velocity is 2pie rad/s. what is the angular velocity at the beginning of the interval?

2. Relevant equations

tried looking at the angular velocity/displacement/acceleraions equations but i dont know how to even begin this question.

3. The attempt at a solution

well i have to find the initial angular velocity and the time interval is also unknown.

2. Dec 9, 2009

### rl.bhat

In the problem angular acceleration, angular displacement and final velocity is given. Can you find an equation which contain initial velocity, final velocity, angular acceleration and angular displacement.

3. Dec 9, 2009

### blaze33

yes but it also has time, which is uknown.

4. Dec 9, 2009

### jegues

Lol at U of M exam questions ;). This one's simple, the key is constant acceleration.

w^2 = Wo^2 +2(alpha)(deltatheta) should do the trick ;)

5. Dec 9, 2009

### blaze33

lol jegues thanks.
hope the exam will be simpler than that haha