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The speed of a swimmer with respect to t...

The speed of a swimmer with respect to the water is v, the speed of the stream is u. In what direction should the swimmer move to reach the opposite point on the other bank of the river? How long will he swim if the width of the river is `l`?

Text Solution

Verified by Experts

The correct Answer is:
`sin alpha = u//v; t = l//v cos alpha`.
For the swimmer not to drift with the steam, the condition `-v_(x)+ + u=0` must be satisfied (see fig.). Hence the given answer. The problem has a solution for `Iv gt u`.
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Knowledge Check

  • A man can swim in still water at a speed of 6 kmph and he has to cross the river and reach just opposite point on the other bank.If the river is flowing at a speed of 3 kmph ,and the width of the river is 2km , the time taken to cross the river is (in hours)

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    `2/3`
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    `2/sqrt45`

  • If speed of water in river is 4 m/s and speed of swimmer with respect to water is 3 m/s, then in which direction the swimmer must swim so that he will reach directly opposite end?

    A
    `127^(@)` with direction of river flow
    B
    `60^(@)` with direction of river flow
    C
    `143^(@)` with direction of river flow
    D
    Swimmer will never reach directly opposite end

  • 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?

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