## In This post you will get answer of Q.

A river is flowing from west to east with a speed $5,m,s^{-1}$. A swimmer can swim in still water at a speed of $10,ms^{-1}$.

If he wants to start from point $A$ on south bank and reach opposite point $B$ on north bank, in what direction should he swim?

Solution:

Here, Velocity of swimmer in still water,

$v_s = 10 ,ms^{-1}$

Velocity of water flowing in river,

$v_r = 5 ,m s^{-1}$

From figure,

$sin,theta=frac{v_{r}}{v_{s}}=frac{5}{10}=frac{1}{2}$

$theta=sin^{-1}left(frac{1}{2}right)$

$=30^{°}$ west of north