Adisk of mass 3.0 kg and radius 65 cm with a small mass of 0.07 kg attached at the edge is rotating at 2.2 rev/s. the small mass suddenly flies off of the disk. what is the disk's final rotation rate (in rev/s)?

Explanation:

Given that

Mass of disc,M=3 kg

radius r= 65 cm

Mass of small mass ,m=0.07 kg

Initial speed = 2.2 rev/s

If external torque is zero then angular momentum of system will remain conserve.

Moment of inertia of disc at initial condition

Moment of inertia of disc at final condition

So from conservation of angular momentum

This is final speed of disc after small mass flies off from the disc.

see earlier