Question

A river is flowing from west to east with a speed of 5 m/ min. A man can swim in still water with a velocity I On)/ min. In which direction should the man swim so as to take the shortest possible path to go to the south.

Answer 1

Correct Question:-

• A river is flowing from west to east with a speed of 5 m/ min. A man can swim in still water with a velocity 10m/min min. In which direction should the man swim so as to take the shortest possible path to go to the south.

___________

Given :-

• Velocity of river = 5m /min
• Relative Velocity if swimmer.

To find : Direction of man swim.

Conversion:-

• Velocity of river = 5 m/min = 1 /12 m/s
• Relative velocity of swimmer = 10 m/min = 1/6 m/s

SolutioN:-

➟ Relative velocity of swimmer Cosθ = velocity of river

➟ 1 /6 Cosθ = 1/12

➟ Cosθ = 6 /12

➟ Cos θ = 1/2

➟ Cosθ = Cos π /3

➟ θ = π/3

➟ θ = 60°

❝Hence, Swimmer will swim 60° to the west direction.❞

For diagram see the image :-

Vmr = relative velocity of swimmer

Vr = Velocity of river

Answer 2

Answer:

Given :-

Velocity of river = 5m /min

Relative Velocity if swimmer.

To find : Direction of man swim.

Conversion:-

Velocity of river = 5 m/min = 1 /12 m/s

Relative velocity of swimmer = 10 m/min = 1/6 m/s

SolutioN:-

➟ Relative velocity of swimmer Cosθ = velocity of river

• 1 /6 Cosθ = 1/12
• Cosθ = 6 /12
• Cos θ = 1/2
• Cosθ = Cos π /3
• θ = π/3
• θ = 60°