The 30-lb flywheel A has a radius of gyration about its center of 4 in. Disk B weighs 50 l...

The 30-lb flywheel A has a radius of gyration about its center of 4 in. Disk B weighs 50 lb and is coupled to the flywheel by means of a belt which does not slip at its contacting surfaces. If a motor supplies a counterclockwise torque to the flywheel of M = (50t) lb • ft, where t is in seconds, determine the time required for the disk to attain an angular velocity of 60 rad/s starting from rest.