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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceDiagram basedMediumMulti-step

JEE Main 17 March 2021, Shift 2, Physics Q5

Question 5 of 90 in this shift, Physics question 5 of 30, Section A.

Two identical blocks A and B each of mass m resting on the smooth horizontal floor are connected by a light spring of natural length L and spring constant K. A third block C of mass m moving with a speed vv along the line joining A and B collides with A. The maximum compression in the spring is

The figure, in words

Three blocks in a row on a horizontal floor line: block C (labelled m) on the left with an arrow pointing right towards block A (labelled m), which is connected by a spring to block B (labelled m) on the right.
  1. (1)m2K\sqrt{\frac{m}{2K}}
  2. (2)vm2Kv\sqrt{\frac{m}{2K}}Official answer
  3. (3)mvK\sqrt{\frac{mv}{K}}
  4. (4)mv2K\sqrt{\frac{mv}{2K}}

Official answer

Option 2

NTA final key.

Chapter
Work, Energy and Power
Topic
Collisions
Idea tested
Spring-Mass Impact

Same idea in other shifts

Asked 2× in all
  1. 3 Apr 2025, Shift 2 · Q29Consider two blocks A and B of masses m1=10m_1 = 10 kg and m2=5m_2 = 5 kg that are placed on a frictionless table. The block A moves with a…MediumSingle correctHas a figure

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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.