JEE Main 2021 · PhysicsNumerical answerNumerical valueEasyCalculation

JEE Main 31 August 2021, Shift 1, Physics Q24

Question 24 of 90 in this shift, Physics question 24 of 30, Section B.

A block moving horizontally on a smooth surface with a speed of 40 ms

^{-1}

splits into two equal parts. If one of the parts moves at 60 ms

^{-1}

in the same direction, then the fractional change in the kinetic energy will be

x

: 4 where

x

= __________.

Official answer

NTA final key.

Chapter: Work, Energy and Power
Topic: Center of Mass
Idea tested: COM Velocity Conservation

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Asked 4× in all

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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.