[填空题]
The forearm in Fig. 8–4lfts1i3t2 h n d7 xu8zgry14.)wsnv-v 5 accelerates a 5h n))vubtbhk-q7: in*pd +rf7n ag4*ru;pcl 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