A river is flowing from west to east with a speed 5 m s-1. A swimmer can swim in still water at a speed of 10 ms-1. If he wants to start from point A on south bank and reach opposite point B on north bank, in what direction should he swim?

Question

A river is flowing from west to east with a speed 5 m s-1. A swimmer can swim in still water at a speed of 10 ms-1. If he wants to start from point A on south bank and reach opposite point B on north bank, in what direction should he swim? (A) 30° east of north (B) 60° east of north (C) 30° west of north (D) 60° west of north

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/fce7984d24f76205b210a4dbf176b69a-.jpeg" /> Here, Velocity of swimmer in still water, vs = 10 ms-1 Velocity of water flowing in river, vr = 5 m s-1 From figure, sin θ=(vr/vs)=(5/10)=(1/2) θ=sin-1((1/2)) =30Â° west of north

Q. A river is flowing from west to east with a speed $5 m s^{- 1}$ . A swimmer can swim in still water at a speed of $10 m s^{- 1}$ .
If he wants to start from point $A$ on south bank and reach opposite point $B$ on north bank, in what direction should he swim?

$3 0^{°}$ east of north

$6 0^{°}$ east of north

$3 0^{°}$ west of north

$6 0^{°}$ west of north

Here, Velocity of swimmer in still water,
$v_{s} = 10 m s^{- 1}$
Velocity of water flowing in river,
$v_{r} = 5 m s^{- 1}$
From figure,
$s in θ = \frac{v _{r}}{v _{s}} = \frac{5}{10} = \frac{1}{2}$
$θ = s i n^{- 1} (\frac{1}{2})$
$= 3 0^{°}$ west of north

Q. A river is flowing from west to east with a speed 5ms−1. A swimmer can swim in still water at a speed of 10ms−1. If he wants to start from point A on south bank and reach opposite point B on north bank, in what direction should he swim?

30° east of north

60° east of north

30° west of north

60° west of north