A swimmer can swim in still water at of 10ms^(-1). While crossing a river his average speed is 6ms^(-1). If he crosses the river in the shortest possible time, what is the speed of flow of water?

A swimmer can swim in still water at of 10ms^(-1). While crossing a ri

1.	A swimmer can swim in still water at of 10ms^(-1). While crossing a river his average speed is 6ms^(-1). If he crosses the river in the shortest possible time, what is the speed of flow of water?
Answer» `16ms^(-1)` `4ms^(-1)` `60ms^(-1)` `8ms^(-1)` SOLUTION :The resultant velocity of SWIMMER must be perpendicular to speed of water to cross the river in a shortest TIME `:.v_(s)^(2)=v^(2)+v_(w)^(2)` `v_(w)^(2)=v_(s)^(2)-v^(2)=100-36=64"":.V_(w)=8m//s`