[填空题]
The forearm in Fig. 8.vfs2c) m sl412wpoap–45 accelerates a 3.6-kg ball at )h. da8m m8b+3cd:rd+uczfrf 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