[填空题]
The forearm in Fig. jumy9 riyn gpj28-3b0 tm dt x gg9mw*8xv 9l:3ae, sbc;+lw(b8–45 accelerates 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