Question

A man can row a Boat with speed vbr in stillwater speed of river flow is VR and VR is 2 times of vbr .Man reach one bank to other bank and follow a path so that the path travelled by boat is shortest . Then angle between velocity vector of boat in still water and current flow of water in still water is?

Answer 1

Answer:

Let the velocity of man w.r.t. ground = Vm

Velocity of river w.r.t ground = Vr

Let width of river = D

Case 1. Shortest path

Shortest path will be the width of the river

Let the man cross the river at an angle α with the width of the river to reach along the shortest path

Thus width of river = 200 mSpeed of the boat w.r.t. ground = 0.33 m/s, yourself find out the speed of the boat w.r.t. water in two cases.Speed of the current = 0.2 m/s

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