Question

give solution with proper explanation

Answer 1

Q : A river is flowing from west to east at a speed of 5 m/min . A man on the south bank of the river, capable of swimming at 10 m/min in still water, wants to swim across the river in th^ shortest time.
Then, he should swim in direction.


Final Answer (a) : Due North


Steps and Understanding:
1) Let the speed of man be (v) = 10m/min at angle theta from vertical and speed of river be u = 5m/min

2) Let the width of river be (d).
We will find time taken by man to reach the opposite bank of river in terms of theta.


For diagram and calculation see pic.