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Question 30455
JEE Physics · Hard

Work, Power and Energy: Spring — Two Blocks MCQ

Solve this quality-checked JEE multiple-choice question, then review the correct answer and explanation.

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Spring — Two BlocksHardQuestion 30455

Question

Two blocks (2 kg and 3 kg) are connected by a spring (k = 100 N/m) on a frictionless surface. One is compressed towards the other by 0.2 m and released. Speed of the 2 kg block when spring regains natural length:
  1. A
    1 m/s
  2. B
    √3 m/s
  3. C
    √(6/5) m/s
    Correct
  4. D
    √(2/3) m/s

Correct answer

√(6/5) m/s

Explanation

PE = ½×100×0.04 = 2 J. Momentum: 2v₁ = 3v₂. Energy: ½×2×v₁² + ½×3×v₂² = 2. Solving: v₁² = 6/5, v₁ = √(6/5) ≈ 1.095 m/s.

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