A uniform disk has a mass of 3.7 kg and a radius of 0.40 m. The disk is mounted on frictionless bearing and is used as a turntable. The turntable is initially rotating at 30 rmp. A thin-walled hollow cylinder has the same mass and radius as the disk. It is released from rest, just above the turntable, and on the same vertical axis. The hollow cylinder slip on the turntable for 0.20 s until it acquires the same final angular velocity as the turntable.
a) Find the final angular speed of the system.
b) What is the final angular momentum of the system?
c) Compere the initial and final kinetic energy of the system. Is the KE conserved?