[问答题]
Two blocks, each of mass m, are attached to the enilfb 4mrz*i99+2liwpe2a u7myf( +v ads of s;e5/ +e nontcug8k 5da massless rod which pivots as shown in Fig. 8–40. Initially the rod is held in the horizontal position and then gs;5u cnd +ok/ete5n8 released. Calculate the magnitude and direction of the net torque on this system.