[填空题]
A small 650-gram ball on the end xq lgyhy5/ 5k3-7zqxg of a thin, light rod is rotatetae35fogj-v4l x w zukfj0 +/;d in a horizontal circle of radius 1.2 m. a+jjv/ew ; 5f0fx-tlgokzu43 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. $m \cdot N$