[填空题]
A small 650-gram ball on the eljbz i5*xv1 e is81- wba75mkwnd of a 6(i)hn1tqmp 4hwa-ts thin, light rod is rotated in a horizontal circle of radius 1.2 m. Calculmp)sat1-it hhw46n( qate (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. $m \cdot N$