The stream of a river is flowing with a speed of 2 km/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 to cross the river straight?
(1) 60º (2) 90º (3) 150º (4) 120º
Correct option (4) 120º
Explanation:
V_{m} sin θ = Vr
4 sin θ = 2
Sin θ = 1/2
θ = 30º
Angle from river flow
= 30º + 90 º = 120º