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Question 30328
JEE Physics · Hard

Rigid Body Dynamics: Angular Momentum Conservation MCQ

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Angular Momentum ConservationHardQuestion 30328

Question

A man stands on a frictionless rotating platform (I_platform = 100 kg·m²) at ω = 2 rad/s. He holds a 2 kg dumbbell in each hand at 1 m from axis. He brings them to the axis (r ≈ 0). New ω is:
  1. A
    2.06 rad/s
    Correct
  2. B
    2 rad/s
  3. C
    4 rad/s
  4. D
    1 rad/s

Correct answer

2.06 rad/s

Explanation

Initial I = 100 + 2×2×1² = 104 kg·m². L = 104×2 = 208. Final I = 100. ω_f = 208/100 = 2.08 ≈ 2.06 rad/s.

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