Starting from rest, a 12 cm diameter compact disk takes 2.4 s to reach its operating angular velocity of 2030 rpm. Assume that the angular acceleration is constant. The disk's moment of inertia is 2.5 10-5 kg·m2.
a) How much torque is applied to the disk?
? N·m
(b) How many revolutions does it make before reaching full speed?
? revolutions