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Question 30576
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Center of Mass, Momentum and Collision: Advanced — Explosion Kinetics MCQ

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Advanced — Explosion KineticsHardQuestion 30576

Question

A 12 kg body at rest explodes into three 4 kg pieces. Two move at 5 m/s each at 90° to each other. KE released in the explosion is:
  1. A
    100 J
  2. B
    75 J
  3. C
    125 J
  4. D
    150 J
    Correct

Correct answer

150 J

Explanation

Two pieces: p₁ = (20, 0), p₂ = (0, 20). Third: p₃ = −(20, 20). |p₃| = 20√2. v₃ = 20√2/4 = 5√2 m/s. KE_total = 2×½×4×25 + ½×4×50 = 100 + 100 = 200 J. Total released = 200 J.

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