[填空题]
The forearm in Fig. 8–45kw)-v zj4u6vpyuqt0,ou jk x;qe29sk m*2q b7k o1fk1s4k2iz/kzr5aaccelerates 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