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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceAssertion–reasonEasyConceptual

JEE Main 26 February 2021, Shift 1, Physics Q2

Question 2 of 90 in this shift, Physics question 2 of 30, Section A.

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Body ‘P’ having mass M moving with speed ‘u’ has head-on collision elastically with another body ‘Q’ having mass ‘m’ initially at rest. If m << M, body ‘Q’ will have a maximum speed equal to ‘2u’ 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 :
  1. (1)Both A and R are correct and R is the correct explanation of A.Official answer
  2. (2)Both A and R are correct but R is NOT the correct explanation of A.
  3. (3)A is correct but R is not correct.
  4. (4)A is not correct but R is correct.

Official answer

Option 1

NTA final key.

Chapter
Work, Energy and Power
Topic
Collisions
Idea tested
1D Elastic Collisions

Same idea in other shifts

Asked 2× in all
  1. 18 Mar 2021, Shift 2 · Q2An object of mass m1m_1 collides with another object of mass m2m_2, which is at rest. After the collision the objects move with equal…MediumSingle correct

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.