[填空题]
The forearm in Fig. 8–45 acce q9 g69hw7q*b;qpjl1tl .qbxiooxa (1wny0h2 9fvpt-zuqrg89+pi 8 +;yuw xilerates 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