[填空题]
The forearm in Fig. nlw ) zf gu1 0l62th+6blwyc7b qe0 b(cx3nj(k rcryzj*l85()xdk z2m8–45 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