A uniform disc of mass 2kg and radius 1m is mounted on an horizontal axle supported on fixed friction less bearings. A light cord is wrapped around the rim of the disc and mass of 1kg is tied to the free end. If it is released from rest,
(A) the tension in the cord is 5N
(B) in first 4 seconds the angular displacement of the disc is 40 rad.
(C) the work done by the torque on the disc in first 4 sec. is 200J
(D) the increase in the kinetic energy of the disc in the first 4 seconds is 200J.
