[问答题]
Two blocks, each of mass hibj94)ksi.- dzzt pvm -:z5d m, are attached to the end3lw/(s,2k6 crjphiy qve2 x 3vs of a massless rod which pivots as shown in Fig. 8–40. Initially the rod is held in the horizontal position and then released. Calculate the magnitude and direction of the net torque on thiqy, (kj/l vpvr3h2ex 2ic3ws6s system.