The vector difference between the absolute velocities of two bodies is called their relative velocity. The concept of relative velocity enables us to treat one body as being at rest while the other is in motion with the relative velocity. This jormalism greatly simplifies many problems. If `vecv_(A)`is the absolute velocity of a body A and `vec_(B)`that of another body B then the relative velocity of A in relation to B is `vec_(AD)=vecV_(A)-vecv_(B)` and `vecv_(BA)=vecv_(B)`-`vecv_(A)`.
The principle follows here is that the relative velocity of two bodies remains unchaged if the same additional velocity is imparted to both the bodies. A simple way of carrying out this operation is to be represent the velocities in magnitude and direction from a common point. Then the line joining the tips of the vectors represents the relative velocity
Q A river is flowing from west to east at a speed of 5 m/s. A man on the south bank of the river, capable of swimming at 10 m/s in still water, wants to cross the river without drifting, he. should swim

Options

A. due north
B. `30^(@)` east of north
C. `30^(@)` west of north
D. `60^(@)` east of north

Answer

C