Question

A boat moves relative to water with a velocity
which is 1/2 times the river flow velocity. At
what angle to the stream direction must the
boat move to minimize drifting.​

Answer 1

Answer:

Explanation:

The velocity at which the boat is moving must be perpendicular to the velocity of the river (v) in order to minimize the drift.

If we take the velocity of the boat while in still water to be v and it makes an angle (x) with the velocity of the flowing river which is v/2 according to the question then the velocity of the boat moving along the direction of the moving water will be vcosx + v/2.

Hence to minimize the drift we have to equate the above value with zero . This will make the above conditions fulfiled.

vcosx + v/2=0

cosx = 120.

So, 120 angle is required to to make the stream direction to make minimum drift.