[填空题]
A small 650-gram ball on the end of a thin, light rod. ee(+ec)jywvf qd* 0ey*isco 1rh 1c/ is rotated in a horizst :rhm6ll4hiu9q )fakd9 (kn2(pro2 ontal circle of radius 1.2 m. Calculatet kr2 fhpiloads n:()m h kuq2l9(694r (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. $m \cdot N$