A grinding wheel is in the form of a uniform solid disk of radius 7.08 cm and mass 2.04 kg. it starts from rest and accelerates uniformly under the action of the constant torque of 0.610 N·m that the motor exerts on the wheel. How long does the wheel take to reach its final operating speed of 1200 rev/ min?
(note that moment of inertia of a disk is given by i = 0.5xmr²)