1. Nov 7, 2005

### hoseA

A.)A dentist's drill starts from rest. After 4.95 s
of constant angular acceleration, it turns at a
rate of 28600 rev/min.
Find the drill's angular acceleration. An-

B.)Find the angle through which the drill rotates

B.) [(28600*2pi)/60] * 4.95 = 14825 rad. (but this is not the right answer?)

Am I using the wrong formula? Any help appreciated.

2. Nov 7, 2005

### Staff: Mentor

This assumes that the speed is constant at (28600*2pi)/60 rad/s. But the speed is not constant; the drill starts from rest and accelerates.

3. Nov 7, 2005

### hoseA

Thanks so much. Didn't realize that. So it's theta = .5 (605.047)(4.95^2)