[问答题]
Two blocks, each of mass m, are attacheda:yui.5 fndtyf.o 91p to the ends of a mas /bunwf 688bkwsless rod which pivots as shown in Fig. 8–40. Initikwf8unb6 /b8wally the rod is held in the horizontal position and then released. Calculate the magnitude and direction of the net torque on this system.