[填空题]
The forearm in Fig. 8–45 accelerates a 3.6-kgi6l,g qe gy31q ball at 7 frc vlv36(ic;jm ; xit7(snk0w-y m9y $m/s^2$ 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