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PHYS 221 · Chapter 8
Momentum & collisions
Textbook
8.3 Conservation of momentum
What changes during a collision?
For an isolated system, the total momentum before and after a collision remains constant.
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
Momentum is conserved even when kinetic energy is not.
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Why can momentum stay constant if energy is lost?
Energy changes form—often into heat, sound, or deformation. Momentum is still conserved when no external force acts.
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