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JEE Main 202126 FebruaryMorning Shift
Exam
JEE Main
Year
2021
Date
26 February
Shift
Morning Shift
Subject
Physics
Chapter
Center of Mass, Momentum and Collision

JEE Main 2021 · 26 February · Morning Shift · Physics · Center of Mass, Momentum and Collision

Given below are two statements: one is labelled as Assertion A and...

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : Body PP having mass MM moving with speed uu has head-on collision elastically with another body QQ having mass mm initially at rest. If m≪Mm ≪ M, body QQ will have a maximum speed equal to 2u2u after collision.

Reason R : During elastic collision, the momentum and kinetic energy are both conserved.

In the light of the above statements, choose the most appropriate answer from the options given below:

Options

  1. AA is correct but R is not correct.
  2. BA is not correct but R is correct.
  3. CBoth A and R are correct and R is the correct explanation of A
  4. DBoth A and R are correct but R is NOT the correct explanation of A

Correct answer

C. Both A and R are correct and R is the correct explanation of A

Step-by-step solution

For e=1e = 1 & second body at rest

V2=2m1u1m1+m2=2u(M)M+m≃2u{V}_{2} = \dfrac{2{m}_{1}{u}_{1}}{{m}_{1} + {m}_{2}} = \dfrac{2u\left(M\right)}{M + m} ≃ 2u

Since M>>mM > > m

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