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Physics · Motion in one Dimension

JEE Main 2024 — 6 April, Shift 1 — Question 47

A train starting from rest first accelerates uniformly up to a speed of 80 km/h80 \mathrm{~km} / \mathrm{h} for time tt, then it moves with a constant speed for time 3 t . The average speed of the train for this duration of journey will be (in km/h\mathrm{km} / \mathrm{h} ) :

  1. Option A:

    80

  2. Option B:

    70

    Correct
  3. Option C:

    30

  4. Option D:

    40

Answer: B

Step-by-step solution

Average speed = total distance  time taken =\frac{\text { total distance }}{\text { time taken }}

=80×t2+80×3t4t=70 km/hr=\frac{\frac{80 \times \mathrm{t}}{2}+80 \times 3 \mathrm{t}}{4 \mathrm{t}}=70 \mathrm{~km} / \mathrm{hr}

Answer key and solution verified before publishing.

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Exam
JEE Main 2024
Paper
6 April, Shift 1
Subject
Physics
Chapter
Motion in one Dimension
Topic
Uniformly Accelerated Motion
A train starting from rest first accelerates uniformly up to a speed… | JEE Main 2024 PYQ with Solution · DhiX AI