[填空题]
A small 650-gram ball on the end oztf c5ll8c,y5 f a thin, light rm*in-bvx2a yd w gyop3jwk**;j /2 vv/od is rotated in a horizontalwiw-ymp j2*d vxb aoyn /**23;jv/k gv circle of radius 1.2 m. Calculate (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. $m \cdot N$