[填空题]
A small 650-gram ball on the lh*cvme 6t6i,wn2n /;lrr-a;t0t ui uend of a 2ie/veb;02zr/iw )ao )w* htizz -wp vthin, light rod is rotated in a horizontal circle of radius 1.2 m. we-v/ 2tie ap/))w; hwoizi*zb0rzv2 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. $m \cdot N$