[填空题]
A small 650-gram ball on the end of a thin, light rod i mkfmej)m q)mhs*9d+w ii2y*8 2 cg5ews rotated in a horizojs6ifrtso0v k+ h28 ;wntal circle of radius 1.2 m. Calcula 2 k0sisr; 8o+hv6fjwtte (a) the moment of inertia of the ball about the center of the circle, $kg \cdot m^2$ (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 the rod’s moment of inertia and air resistance. $m \cdot N$