[填空题]
The forearm in Fig. 8–4)t*kvm-x ,l nn -aewju- sw9 eia-4mz75 acceler+g qgj2 j d*kb:/yjw3pates 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