The stream of a river is flowing with a speed of `2km//h`. A swimmer can swim at a speed of `4 km//h`. What should be the direction of the swimmer with respect to the flow of the river ot cross the river straight ?

Options

A. `90^(@)`
B. `60^(@)`
C. `120^(@)`
D. `150^(@)`

Answer

C

Explanation

For no drifting, `sin theta = (u)/(v_(m))=2/4 = 1/2`
`:. theta = 30^(@)`
Hence direction with flow of rivers is
`alpha= 180- theta=120^(@)`