[填空题]
The forearm in Fig. 8–45 accele 3-k-tx5 mn3oh+,v5q ipcs -hsnluj9trates a 3.6-kg oem mpp+,3c(x 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