A man swims at 2 m s⁻¹ in still water and wants to cross a river flowing at √3 m s⁻¹ along the shortest possible path. At what angle to the water current should he swim?
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Question

A man swims at 2 m s⁻¹ in still water and wants to cross a river flowing at √3 m s⁻¹ along the shortest possible path. At what angle to the water current should he swim?

G1 Physics · Accepted Answer

For zero drift, swimmer's upstream component must equal √3. Thus 2cosθ=-√3 with θ measured from current direction, giving θ=150°. Option B.