[填空题]
The forearm in Fig. 8–45 /c;v+emqg a2 gk0 se:eye9kt*8 :iuty uz :qx4accelerates 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