Topic: Relative velocity· Kinematics

The speed of a swimmer in still water is 20 m/s. The speed of river water is 10 m/s and is flowing due east. If he is standing on the south bank and wishes to cross the river along the shortest path, the angle at which he should make his strokes w.r.…

The speed of a swimmer in still water is 20 m/s. The speed of river water is 10 m/s and is flowing due east. If he is standing on the south bank and wishes to cross the river along the shortest path, the angle at which he should make his strokes w.r.t. north is given by :

1. \(30^\circ\) west

2. \(0^\circ\)

3. \(60^\circ\) west

4. \(45^\circ\) west

Doubtly Asked 30 Oct 2026 NEET UG 2019 Practice test neet Save WhatsApp Report

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Answer: 1. \(30^\circ\) west

To cross along the shortest path (straight north), the swimmer's velocity component along the river flow must cancel the river's speed.

If he points at angle \(\theta\) west of north: \(20\sin\theta=10\), so \(\sin\theta=\tfrac12\) and \(\theta=30^\circ\) west of north.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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The speed of a swimmer in still water is 20 m/s. The speed of river water is 10 m/s and is flowing due east. If he is standing on the south bank and wishes to cross the river along the shortest path, the angle at which he should make his strokes w.r.…

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