Question

A cylinder is pure rolling up an inclined plane. It stops momentarily and then rolls back. The force of friction:

• A. on the cylinder is zero throughout the journey.
• B. is directed opposite to the velocity of the centre of mass throughout the journey.
• C. is directed up the plane throughout the journey.
• D. is directed down the plane throughout the journey.

Answer 1

The correct option is C is directed up the plane throughout the journey.

During ascending up the plane, the cylinder is trying to push the plane backward thereby getting a forward push and during descending down the plane the frictional force again points up the plane as it is responsible to provide the rolling motion. In the second case frictional force is the driving force for rolling.