A rod of mass m and length l is lying on a horizontal table. The work done in making it stand vertically on one end will be

A rod of mass m and length l is lying on a horizontal table. The work done in making it stand vertically on one end will be

The bob of a simple pendulum (mass m and length l) dropped from a horizontal position strikes a block of the same mass elastically placed on a horizontal frictionless table. The K.E. of the block will be

A uniform chain of length L and mass M is lying on a smooth table and one third of its length is hanging vertically down over the edge of the table. If g is acceleration due to gravity, the work required to pull the hanging part on to the table is [IIT 1985]