A man isswimming against current such that his position with respect to the river bank remains unaltered.Is the man doing any work ?

A man isswimming against current such that his position with respect t

1.	A man isswimming against current such that his position with respect to the river bank remains unaltered.Is the man doing any work ?
Answer» Solution :The relative DISPLACEMENT of the man with respect to the river BANK is zero . So, no WORK is done by the man. The resistive force of river water just BALANCES the force applied by the man . So, this case is similar to a force applied against static FRICTION.