[填空题]
The forearm in Fig. 8–45 a,;+blw9 rmtt) 0;0jnt3fojr r6we qbh uatl0tm*x/3yqa; 2l xd )wb 8fccelerates a 3.6-kg ball at 7 $m/s^2$ by means of the triceps muscle, as shown. Calculate
(a) the torque needed, $m \cdot N$
(b) the force that must be exerted by the triceps muscle. Ignore the mass of the arm. N