JEE Main 2020PhysicsCenter of Mass Momentum and CollisionEasyNumerical

JEE Main 2020 — Center of Mass Momentum and Collision Question with Solution

JEE Main 2020 (08 Jan Shift 1)

Question

A body A of mass m=0.1 kg has an initial velocity of 3i^ m s-1. It collides elastically with another body B of the same mass which has an initial velocity of 5j^ m s-1. After the collision, A moves with a velocity v→=4i^+j^ m s-1. The energy of B after the collision is written as x10 J. The value of x is

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Correct answer
1

Step-by-step explanation

Using the principle of conservation of linear momentum

0.1×3i^ + 0.1×5j^ = 0.1×4i^+j^ + 0.1×v→

v→=-i^ + j^ m s-1

v=v→=2 m s-1

KB=12×0.1×v2=110 J

x=1

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About this question

This is a previous-year question from JEE Main 2020, covering the Center of Mass Momentum and Collision chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.