A small motor is mounted on the axis of a space probe with its rotor (the rotating part of the motor) parallel to the axis of the probe. Its function is to control the rotational position of the probe about the axis. The moment of inertia of the probe is 6000 times that of the rotor. Initially, the probe and rotor are at rest. The motor is turned on and after some period of time, the probe is seen to have rotated by positive 32.6 degrees.

Through how many revolutions has the rotor turned?

1 answer

what is 6000*32.6 degrees?

momentum is conserved.
Iprobe*wprobe=Imotor*wmotor
INtegrate both sides over the same time

6000*wprobe*t=1*wm*t

6000*wp*t=wm*t
but wp*t=32.6
so the displacement of the motor is 6000*32.6 degrees