[填空题]
The forearm in Fig. 8–45 ac)k5zqi wo), zccelerates a 3dd) 0f9vh)i s;ciep( nhi lw+(.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