A light thread with a body of mass m tied to its end is wound on a

Question:

A light thread with a body of mass m tied to its end is wound on a uniform solid cylinder of mass M and radius R (Fig. 1.55). At a moment t = 0 the system is set in motion. Assuming the friction in the axle of the cylinder to be negligible, find the time dependence of
(a) The angular velocity of the cylinder;
(b) The kinetic energy of the whole system.