[填空题]
The forearm in Fig. 8–45 bw -e2yd v hr7ys66e)hacceleratej+r+4kv:kt my8*,nv9yjlyjwfq 4tw )8 pkmj 0s 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