Question

PLEASE ANSWER AND EXPLAIN!!!
A person aiming to reach the exactly opposite point on the bank of a stream is swimming with a speed of 0.50 m/s at an angle of 120° with the direction of flow of the stream. The speed of the stream is?


a) 1.0 m/s

b) 0.50 m/s

c) 0.25 m/s

d) 0.43 m/s

Answer 1

Do you know when you have to reach exactly opposite point of journey then you should travel in direction opposite to flow of stream otherwise you can not reach to opposite point •

we have(see pic)

In above figure

Vᵣ = velocity of river or stream = ?

Vs = velocity of swimmer = 0.5 m/s

V= resultant velocity

given angle is total angle ie 90+30= 120

From figure in triangle Δ

sin θ = p/ h

sin 30⁰ = Vᵣ / Vs

1/2 = Vr/ 0.5

so Vr= 1/4 ie

Vr = 0.25 m/s so velocity of river is 0.25 m/ s

hope this helps