Question

A body of mass m kg is lifted by a man to a height of one metre in 30 sec. Another man lifts the same mass to the same height in 60 sec. The work done by them(approximately) are in the ratio

• A. 1 : 2
• B. 1 : 1
• C. 2 : 1
• D. 4 : 1

Answer 1

The correct option is B 1 : 1

Work done does not depend on time. Work done is a product of Force and displacement along the direction of force. It is mentioned already that the height that the object was displaced is same in both cases, so the work done must be same. To understand it from potential energy perspective, The change in potential energy is same in both the cases.