Question

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
A. 3 m `s^(-1)`
B. 5 m `s^(-1)`
C. 7 m `s^(-1)`
D. 2 m `s^(-1)`

Answer 1

Correct Answer - B

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