JEE Mains · Physics · STD 11 - 3.2 motion in plane
The speed of a swimmer is \(4\,km\,h ^{-1}\) in still water. If the swimmer makes his strokes normal to the flow of river of width \(1\,km\), he reaches a point \(750 \,m\) down the stream on the opposite bank.The speed of the river water is \(.........km h ^{-1}\)
- A \(3\)
- B \(2\)
- C \(1\)
- D \(30\)
Answer & Solution
Correct Answer
(A) \(3\)
Step-by-step Solution
Detailed explanation
time to cross the River width \(\omega=1000\,m\) \(\text { is }=\frac{1\,km }{4\,km / h }\) Drift \(x = Vm / g \times t\) Where \(Vm / g\) is velocity of River w.r. to ground. \(x = Vm / g \times \frac{1}{4}=750\,m =\frac{3}{4}\,km\) \(Vm / g =3 km / hr\) Ans is \(3\,km / hr\).
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