A river is flowing due east with a speed 3 ms-1. A swimmer can swim in still water at a speed of 4 ms-1. If swimmer starts swimming due north, then the resultant velocity of the swimmer is

Question

A river is flowing due east with a speed 3 ms-1. A swimmer can swim in still water at a speed of 4 ms-1. If swimmer starts swimming due north, then the resultant velocity of the swimmer is (A) 3 ms-1 (B) 5 ms-1 (C) 7 ms-1 (D) 2 ms-1

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/2ee1c304d815ca6a331d81e670321f8e-.jpeg" /> Here, Velocity of water flowing in river, vr = 3 m s-1 Velocity of swimmer in still water, vs = 4 m s-1 From figure, The resultant velocity of the swimmer is v=√v2s+v2r =√(4)2+(3)2 =√25 =5 ms-1

Q. A river is flowing due east with a speed $3 m s^{- 1}$ . A swimmer can swim in still water at a speed of $4 m s^{- 1}$ . If swimmer starts swimming due north, then the resultant velocity of the swimmer is

$3 m s^{- 1}$

$5 m s^{- 1}$

$7 m s^{- 1}$

$2 m s^{- 1}$

Here,
Velocity of water flowing in river, $v_{r} = 3 m s^{- 1}$
Velocity of swimmer in still water, $v_{s} = 4 m s^{- 1}$
From figure,
The resultant velocity of the swimmer is
$v = v_{s}^{2} + v_{r}^{2}$
$= (4)^{2} + (3)^{2}$
$= 25$
$= 5 m s^{- 1}$

Q. A river is flowing due east with a speed 3ms−1. A swimmer can swim in still water at a speed of 4ms−1. If swimmer starts swimming due north, then the resultant velocity of the swimmer is

3ms−1

5ms−1

7ms−1

2ms−1