A dentist’s drill starts from rest. After 1.28 s

Question

of constant angular acceleration it turns at a
rate of 38840 rev/min.
Find the drill’s angular acceleration.
Answer in units of rad/s^2

Throughout what angle does the drill rotate
during this period?
Answer in units of rad.

Answer 1

each revoution= 2PI radians
avg speed=38840/2 rev
angletotal=2PI*avgspeed*1.28/60 radians