The pulley arrangements of Figs. (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=2mg`. The acceleration of m is the same in both cases

Options

A. zero
B. More than that in case (b)
C. Less than that in case (b)
D. Equal to that in case (b)

Answer

C

Explanation

Case (a): `a_(1)=(2mg-mg)/(3m)=(g)/(3)`
Case (b): `a_(2)=(2mg-mg)/(m)=g`.