Question

- A man swims across a river with speed of 5 kmh (in still water), while a boat goes upstream
with speed 12 km h' (in still water). How fast and in which direction does the man appear to go
to the boatman? Given that the speed of flowing water is 2 km hr!​

Answer 1

The velocity of boat with respect to river

=> Vb = √(2)² + (12)²

=> Vb = √128 m/s

The relative velocity of man with respect to river

=> Vm = √(2)² + (5)²

=> Vm = √29 m/s

The direction in which the man appear to go to the boatman

$= > theta = \cos ^{ - 1} ( \frac{vm}{vb}) \\ = > theta = \cos ^{ - 1}( \sqrt{ \frac{29}{148}) }$

The speed with which man should move faster

$v \: = \sqrt{148 - 29}$

V = √119 km/hr

Hope it helps :)