# Homework Help: Rotation Problem

1. Mar 13, 2013

### KTiaam

1. The problem statement, all variables and given/known data
A merry - go - round rotates clockwise 15 times in 45 seconds. By rubbing against its edge, a child stop it from turning in 15 seconds.

a) find its initial angular velocity (ω)
b) find its angular acceleration ($\alpha$)

3. The attempt at a solution

15 times in 45 seconds means:

in 1 second it makes 1/3 of a revolution

thus in 3 seconds it make on complete revolution

im not sure if im going in the right direction but Angular Velocity is in radians per second.

Am i on the right track? Do i just take the reciprocal of my answer? Please help
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Mar 13, 2013

### TSny

You found that it makes 1/3 revolution per second. Can you convert 1/3 revolution to radians?

3. Mar 13, 2013

### KTiaam

2/3 pi radians?

4. Mar 13, 2013

### TSny

Yes.

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