Can anyone help my start this problem?

[physics_ash82]

A 0.150-m-radius grinding wheel, starting at rest, develops an angular speed of 12.0 rad/s in a time interval of 4.00 s. What is the centripetal acceleration of a point 0.100 m from the center when the wheel is moving at an angular speed of 12.0 rad/s?

 

[quantumdude]

First state the formula for centripetal acceleration. Then look for those quantities in the problem statement.

Give it a try. If you get stuck then post what you have done and where you got stuck. But you must show an attempt at the problem in order to receive help here.

 

[physics_ash82]

Ac= v^2 / r

12^2 / .100 which I got 1440. and the answer is 14.4

 

[mezarashi]

It is true that centripetal acceleration = v^2/r, where v is the tangential velocity.

However, the 12 you are using is angular velocity. You may convert this $$\omega = \frac{v}{r}$$ or use the alternative formula: $$a_c = \omega^2r$$

 

[physics_ash82]

ooh...thanks for the help