A torque of 56 N ? m producing a counterclockwise rotation is applied to a wheel about its axle. A frictional torque of 12 N ? m acts at the axle.

(a) What is the net torque about the axle of the wheel?

(b) If the wheel is observed to accelerate at a rate of 4 rad/s2 under the influence of these torques, what is the rotational inertia of the wheel?