Conservation of Momentum
Momentum survives every collision; kinetic energy does not. This simulation runs elastic and inelastic collisions side by side and totals both quantities before and after, so the distinction becomes a measurement rather than a definition.
How to use this simulation
- Set the mass and initial velocity of each object
- Switch between elastic, inelastic and perfectly inelastic collisions
- Read the momentum and energy totals before and after
What to look for
- Total momentum is identical before and after every collision
- Kinetic energy is only conserved in the elastic case
- Equal masses colliding elastically simply exchange velocities
The physics behind it
In the absence of external forces, total momentum is conserved: m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂. In an elastic collision kinetic energy is also conserved; in an inelastic one some is converted to heat, sound and deformation, and in a perfectly inelastic collision the objects move off together with the maximum possible energy loss.