Question

Work done by friction can-never be positive.

• A. True
• B. False

Answer 1

The correct option is B False

1. Whenever the displacement of the body is in the direction of the force, the work done by frictional force will be positive.
2. Consider there are two blocks stacked one over the other.
3. If the lower block starts to move slowly in one direction, then there is a frictional force between the two blocks that prevent the sliding of the two blocks.
4. The upper block also moves along with the lower block, that is, in the direction of the frictional force.
5. Hence, the work done by friction is positive in this case.

Hence, the given statement “ Work done by friction can-never be positive ” is false.