[填空题]
The forearm in Fig. 8–45 accelerates a aoq 24 y:bdymag*vk773.6-ktmc + 2-,yr;.ktpnka yg 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