Grade 12 · Physics
Collisions
Why it matters
Conservation laws.
Advanced20m readingPrerequisite: Impulse
What is the difference between elastic and inelastic collisions?
Short answer
In both elastic and inelastic collisions, total momentum is conserved. The difference is kinetic energy: in an elastic collision total kinetic energy is also conserved, while in an inelastic collision some kinetic energy is converted to heat, sound, or deformation. A perfectly inelastic collision is one where the objects stick together and move as one.
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Frequently asked questions
- Is momentum conserved in an inelastic collision?
- Yes. Momentum is conserved in every collision without external forces; only kinetic energy is lost in an inelastic one.
- What is a perfectly inelastic collision?
- One where the colliding objects stick together and move with a single common velocity afterward.