An experimental solid disc flywheel has a 300m diameter and a mass of 70kg. Experiments show that, at all speeds of rotation, the frictional resistance to motion is equivalent to a torque of 0.15Nm. if when the flywheel is rotating at 50 rev/min, the driving power is removed, calculate;

Question

An experimental solid disc flywheel has a 300m diameter and a mass of 70kg. Experiments show that, at all speeds of rotation, the frictional resistance to motion is equivalent to a torque of 0.15Nm. if when the flywheel is rotating at 50 rev/min, the driving power is removed, calculate;
a- the angular retardation
b - time taken for the flywheel to come to rest
c - the total number of revolutions made by the flywheel during retardation.