question_answer

A man can swim with velocity v relative to water. He has to cross a river of width d flowing with a velocity u (u > v). The distance through which he is carried down stream by the river is x. Which of the following statement is correct

A)                 If he crosses the river in minimum time \[x=\frac{du}{v}\]

B)                 x can not be less than \[\frac{du}{v}\]

C)                 For x to be minimum he has to swim in a direction making an angle of \[\frac{\pi }{2}+{{\sin }^{-1}}\left( \frac{v}{u} \right)\] with the direction of the flow of water

D)                 x will be max. if he swims in a direction making an angle of \[\frac{\pi }{2}+{{\sin }^{-1}}\frac{v}{u}\] with direction of the flow of water