Q.
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 :
A) 30° west
B) 0°
C) 60° west
D) 45° west
Explanation
[Solution] $\sin\theta = \frac{v_r}{v_s} = \frac{10}{20}$, so $\theta = 30^\circ$ west of north. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.