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Question 30580
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Center of Mass, Momentum and Collision: Advanced — COM with External Force MCQ

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Advanced — COM with External ForceHardQuestion 30580

Question

A two-particle system has F_ext = 10 N (rightward) acting only on particle 1. Particle 2 has no external force. The COM:
  1. A
    Accelerates rightward at a_cm = 10/(m₁+m₂)
    Correct
  2. B
    Stays at rest because particle 2 has no force
  3. C
    Accelerates at 10/m₁
  4. D
    Is unaffected by the force on particle 1

Correct answer

Accelerates rightward at a_cm = 10/(m₁+m₂)

Explanation

a_cm = F_net_ext / M_total = 10/(m₁+m₂). The COM acceleration depends on the total external force divided by total mass — particle 2's force being zero still contributes to M_total.

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