[问答题]
Two blocks, each of mass m, are attached to the endsv 0b,mg0i4g 9y-fiydo5y* pvt of a massless rod wf8: p ,xsfr0zthich pivots as shown in Fig. 8–40. Initially the rod is held in the horizontal posit,frz 8t:px 0sfion and then released. Calculate the magnitude and direction of the net torque on this system.
