A man can swim in still water ast a speed of 3 km/h. He wants to cross a river that flows at 2 km/h and reach the point directly oposite to his starting point. A. In which diretionshoeld he try to swim (that is, find the angle his body makes wilth the river flow)? b. How much time will he take to cross the river if the river is 500 m wide?

Options

A. `6sqrt(5) mi n`
B. `3sqrt(5) mi n`
C. `2sqrt(5) mi n`
D. `5sqrt(3)mi n`

Answer

A

Explanation

`t=d/(sqrt(v^(2)-u^(2)))=(1//2)/(sqrt(3^(2)-2^(2)))=1/(2sqrt(5))h`
`=60/(2sqrt(5))=30/(sqrt(5))`
`=6sqrt(5) min`