38. (II) A small 350-gram ball on the end of a thin, light rod is rotated in a horizontal circle of radius 1.2 m. Calculate
(a) the moment of inertia of the ball about the center of
the circle, and (b) the torque needed to keep the ball
rotating at constant angular velocity if air resistance exerts
a force of 0.020 N on the ball. Ignore air resistance on
the rod and its moment of inertia.