[填空题]
Calculate the net torque about the axle of the whe0t qzeywvsi21:u0 ajj.+w g9 ue* q1qozb:poonn u:x6 o-v(d2p0 ho0oyl shown in Fig. 8–39. Assume that a friction torque ofp:pny2 :oo-0qdn6*( o hub xv0o1ozqo 0.4 $m \cdot N$ opposes the motion. $m \cdot N$