[填空题]
The forearm in Fig. 8–45 acceihpb1:2h l c uh,ty,p9qy-6 z2odjcl3lerates a 3.6-kg ball at 7 q+4cd :lqe:+gwo(tjq $m/s^2$ 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