A Solid, Uniform, Horizontal Disk with a Diameter of 2 $$\text { (c) What is the angular velocity of the disk (in rpm) after the stone fell onto the disk? }$$

Short Answer

A solid, uniform, horizontal disk with a diameter of 2.0 m and a mass of 4.0 kg freely
rotates at 36 rpm about a vertical axis through its center. A small 0.50-kg stone is suddenly
dropped onto the disk and sticks to the disk at a distance of 80 cm from the axis of
rotation. The figure shows before and after views.
(a) Before the stone fell, what was the moment of inertia of the disk about its central axis?
(b) After the stone stuck, what was the moment of inertia of the system about the same
axis? $$\text { (c) What is the angular velocity of the disk (in rpm) after the stone fell onto the disk? }$$