[填空题]
The forearm in Fig. 8–45 accel6keg l3;/ ig(w2uza7giem .bl erates a 3.6ffwqz1f) 2y+hx*r +fr -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