The stream of a river is flowing with a speed of 2 k m h - 1 . A swimmer can swim at a speed of 4 km h - 1 .…

The stream of a river is flowing with a speed of 2 km h-1. A swimmer can swim at a speed of 4 km h-1. The direction of the swimmer with respect to the flow of the river, to cross the river straight, is
  1. 150°
  2. 90°
  3. 120°
  4. 60°

Solution

To reach the point directly opposite to the starting point, the resultant velocity of swimmer should be as shown in figure.


 
From figure
sinθ=24=12
θ=30°
Angle with flow =90°+30°=120°

Asked in: JEE Main 2019 (09 Apr Shift 1)

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