The pulley arrangements to Fig . (A) and (B) , are identical . The mass of the rope is negligible . In (A) the mass m is lifted up by attaching a mass 2m to the other end of the rope .
In (B) m is lifted up by pulling the other end of the rope with a constant downward force F=2 mg . In which case the acceleration of .m. is more?

Answer

in case of (b)