A uniform rod of length 0.880 m and mass 11.5 kg is balanced on a sharp edge at 0.580 m from the left end. At the left end hangs a mass of 45.0 kg and the right end hangs an unknown mass so that the whole assembly is in equilibrium. Calculate the torque on the center of mass of the rod alone with respect to the pivot point. find the uknown mass as well.