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Physics · Motion in Plane

JEE Main 2026 — 21 January, Evening Shift — Question 38

A river of width 200 m is flowing from west to east with a speed of 18 km/h18 \mathrm{~km} / \mathrm{h}. A boat, moving with speed of 36 km/h36 \mathrm{~km} / \mathrm{h} in still water, is made to travel one-round trip (bank to bank of the river). Minimum time taken by the boat for this journey and also the displacement along the river bank are ____\_\_\_\_ and ____\_\_\_\_ respectively.

  1. Option A:

    20 s and 100 m

  2. Option B:

    40 s and 0 m

  3. Option C:

    40 s and 200 m

    Correct
  4. Option D:

    40 s and 100 m

Answer: C

Step-by-step solution

Minimum time :

tmin⁡=20010=20sect_{\min }=\frac{200}{10}=20 \mathrm{sec}

For round trip =40sec=40 \mathrm{sec}. Displacement along river bank =40×5=200 m=40 \times 5=200 \mathrm{~m}

Solution figure

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Paper
21 January, Evening Shift
Subject
Physics
Chapter
Motion in Plane
Topic
Relative Motion in One Dimension
A river of width 200 m is flowing from west to east with a speed of… | JEE Main 2026 PYQ with Solution · DhiX AI