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Conservation of Momentum

Momentum is conserved in a closed system (no external forces).
Total momentum before collision equals total momentum after collision.

  • Moment ≠ Momentum
  • Impulse ≠ Force
  • Airbags reduce force by increasing impact time (stopping time)
  • Momentum is conserved in closed systems
  • Force depends on stopping time
  • Avoid mixing the words “moment” and “momentum”.
  • Use “change in momentum” in explanations involving impulse.
  • Do not use “impact force” without explaining what happens to impact time.