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A swimmer crosses a flowing stream of width d' to and fro in time t_(1). The time taken to cover the same distance up and down the stream is t_(2), If t_(3) is the time the swimmer would take to swim a distance 2d in still water, then |
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Answer» Solution :Let v be the river velocity and U the velocity of swimmer in still water. Then `t_(1) =2(d/sqrt(u^(2)-v^(2)))`……..(i) `t_(2) =d/(u+v) +d/(u-v) = (2ud)/(u^(2) -v^(2))`…(ii) and `t_(3) =(2D)/u`…….(iii) from equations, (i), (ii), and (iii) `t_(1)^(2) =t_(2)t_(3) |
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