Two masses, mA = 32.0kg and mB = 38.0 kg, are connected by a rope that hangs

Question:

Two masses, mA = 32.0kg and mB = 38.0 kg, are connected by a rope that hangs over a pulley (as in Fig. 8-54). The pulley is a uniform cylinder of radius R = 0.311 m and mass 3.1 kg. Initially mA is on the ground and mB rests 2.5 m above the ground. If the system is released, use conservation of energy to determine the speed of mB just before it strikes the ground. Assume the pulley bearing is frictionless.