Question

A swimmer can swim at a speed of 0.6 m/s with respect to water. She wants to cross a river which is 50 m wide and has a water current of 0.36 m/s. If she wants to reach on other bank at a point directly opposite from her starting point, in which direction she must swim?
OPTIONS:

At right angle to river flow


At 53° with river flow


At 127° with river flow


At 143° with river flow

Answer 1

Answer:

At 127° with river flow

Hope this will help you...

Answer 2

If she wants to reach on other bank at a point directly opposite from her starting point, the direction in which she must swim is at 127° with river flow.

The speed of the swimmer is (u) = 0.6 m/s

The width of the river = 50 m

The speed of the water current is (v) = 0.36 m/s

She wants to reach on the other bank at a point directly opposite from her starting point, so the drift is = 0 m

Suppose she has to swim at an angle of θ with the river flow.

Now, u Cosθ = - v

⇒ Cosθ = - v/u

⇒ Cosθ = - 0.36/0.6

⇒ Cosθ = - 3/5

⇒ Cosθ = 127°

So, the direction in which she must swim is at 127° with river flow.