Question

A man can swim at a speed of `3 km h^-1` in still water. He wants to cross a `500-m` wide river flowing at `2 km h^-1`. He keeps himself always at an angle to `120^@` with the river flow while swimming.
The drift of the man along the direction of flow, when he arrives at the opposite bank is.
A. `(1)/(6 sqrt(3)) km`
B. ` 6 sqrt(3) cm`
C. `3 sqrt(3) km`
D. `(1)/(3 sqrt(3)) km`

Answer 1

Correct Answer - A
(a) `t = (d)/( v sin theta) =(0.5 km)/(3 sin 120^@ km h^-1)=(1)/(3 sqrt(3)) h`
`x = (u + v cos theta) t = (2 + 3 cos 120^@)(1)/(3 sqrt(3)) = (1)/(6 sqrt(3))`.