[填空题]
The forearm in Fig. 8–45 accelert3joy)g )rkcph6)snc68 h9zc ates a 3.6-kg ball at 7 .p+vp)bg . sew$m/s^2$ 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