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 Numerical answer type. Work it out, then open the answer.

Answer: 3. Strokes normal to flow: t = d/vs = 1/4 h Drift = vr t ⇒ 0.75 = vr × 1/4 vr = 3 km h⁻¹

The speed of a swimmer is 4 km h⁻¹ in still water. If the swimmer… | JEE Main 2023 (31 Jan, Shift 1)

Q9JEE Main 2023 · 31 JAN · SHIFT 1Easy

Relative Velocity in Two Dimensions

The speed of a swimmer is $4\text{ km h}^{-1}$ in still water. If the swimmer makes his strokes normal to the flow of river of width $1\text{ km}$ , he reaches a point $750\text{ m}$ down the stream on the opposite bank. The speed of the river water is ___________ $\text{km h}^{-1}$

Numerical answer type. Work it out, then open the answer.

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Answer: 3

Strokes normal to flow: $t = \frac{d}{v_s} = \frac{1}{4}\text{ h}$
Drift $= v_r t \Rightarrow 0.75 = v_r \times \frac{1}{4}$
$v_r = 3\text{ km h}^{-1}$

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Relative Velocity in Two Dimensions question from JEE Main 2023 (31 Jan, Shift 1)

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