Question

A man crossing a river flowing with velocity of 5m/s. He reaches a point directly across at a dustance of 60m in 5sec. His velocity in still wtaer should be

Answer 1

Here, velocity of river water, $v_r=5m/s$
Width of river, $=60m$
Time taken by man in crossing river, $t=5s$
Velocity of man in still water, $v_m=?$

If $v_R$ is the resultant velocity of river water and of the man, then

$v_R=\frac{60}{5}=12m/s$

Thus, $v_m=\sqrt{v_R^2-v_r^2}=\sqrt{{12}^2-5^2}=10.9m/s$