Question

A body moves through a distance of 'm' in the following different ways, the work done is minimum when the body is :

• A. pushed over an inclined plane
• B. lifted vertically upward
• C. pushed over smooth rollers
• D. pushed over a wedge

Answer 1

The correct option is C pushed over smooth rollers

Frictional force acts in direction opposite to the applied force. Thus when a body will be pushed over an inclined plane or lifted vertically upwards the frictional force will act in downward direction which will be greater as compared to when a body is pushed over smooth rollers i.e in this case the frictional force will be less. Thus a lesser force will be required here.