[填空题]
The forearm in Fig. g* emxfq *m:-;voma;c7gvh+c876a hhj-d3z-7md9 m j *xwycww–45 accelerates 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