[填空题]
The forearm in Fig. 8–45 accelerates a 3.6d2,pg4 pnq*np -kg ball at 7 z8f96y hc;l j0 .kuziy0wvs5p$m/s^2$ 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