Motion in a Plane - Result Question 55
58. A person swims in a river aiming to reach exactly opposite point on the bank of a river. His speed of swimming is $0.5 m / s$ at an angle $120^{\circ}$ with the direction of flow of water. The speed of water in stream is
[1999]
(a) $1.0 m / s$
(b) $0.5 m / s$
(c) $0.25 m / s$
(d) $0.43 m / s$.
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Answer:
Correct Answer: 58. (c)
Solution:
- (c)
Velocity of person, $ \vec{v} _m=0.5 m / s$
$ \begin{aligned} & \sin 30^{\circ}=\frac{v_w}{v_m} \Rightarrow v_w=v_m \sin 30^{\circ} \\ & \Rightarrow v_w=\frac{v_m}{2}=\frac{0.5 m / s}{2}=0.25 m / s \end{aligned} $
