A 5-kg quarter of a circular disk with a radius of 500 mm and a radius of gyration kc = 0.25 m is pinned at O. If it is released from rest with the left edge at a vertical position (theta is zero) as shown below, find: a) Its initial angular acceleration b) The reaction force at O in z-y coordinate system c) Its angular velocity when theta reaches 45 degrees (G is the center of gravity)

A 5-kg quarter of a circular disk with a radius of 500 mm and a radius of gyration kc = 0.25 m is pinned at O. If it is released from rest with the left edge at a vertical position (theta is zero) as shown below, find: a) Its initial angular acceleration b) The reaction force at O in z-y coordinate system c) Its angular velocity when theta reaches 45 degrees (G is the center of gravity)