JEE Main 2019PhysicsCenter of Mass Momentum and CollisionMediumMCQ

JEE Main 2019 — Center of Mass Momentum and Collision Question with Solution

JEE Main 2019 (09 Apr Shift 1)

Question

A body of mass 2 kg makes an elastic collision with a second body at rest and continues to move in the original direction but with one fourth of its original speed. What is the mass of the second body?

Choose an option

Show full solutionCorrect option: B
Correct answer
B1.2 kg

Step-by-step explanation


From conservation of linear momentum
mU=mU4+MV . . . (i)
For elastic collision: e=1=V-U4u
V=5U4 . . . (ii)
From equation (i) & (ii),
mU=mU4+M5U4
m=m4+54M  ⇒M=3m5=1.2 kg

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About this question

This is a previous-year question from JEE Main 2019, 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.