[填空题]
The forearm in Fig. 8xe2:eb0u jlgliy; a*kt) gwq4d.g-9 k–45 accele1l k,j me2pv/ir)g.86 kk h0ioaigw5yrates 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