Momentum & Collision Simulator
Set the masses and velocities of two objects, choose a collision type, and watch the result play out. The simulator shows momentum conservation, energy analysis, and step-by-step solutions for elastic, inelastic, and partially inelastic collisions. All calculations run in your browser.
| Before | After | Conserved | |
|---|---|---|---|
| Momentum | 2 kg·m/s | 2 kg·m/s | Yes |
| Kinetic Energy | 22 J | 22 J | Yes |
Reference Guide
Conservation of Momentum
Momentum is the product of mass and velocity. In any closed system, the total momentum before a collision equals the total momentum after, regardless of collision type.
This principle holds for all collision types. It follows directly from Newton's third law: the forces the two objects exert on each other are equal and opposite, so the total impulse is zero.
Elastic Collisions
In an elastic collision, both momentum and kinetic energy are conserved. These two constraints together determine the final velocities uniquely.
For equal masses, the objects swap velocities. This is why a billiard ball stops dead when it hits another ball of the same mass head-on.
Inelastic Collisions
In an inelastic collision, momentum is conserved but kinetic energy is not. Some kinetic energy is converted into heat, sound, or deformation.
A perfectly inelastic collision loses the maximum possible kinetic energy while still conserving momentum. The objects move together as a single unit after the collision.
Coefficient of Restitution
The coefficient of restitution measures how "bouncy" a collision is. It is defined as the ratio of relative speeds after and before the collision.
When the collision is perfectly elastic. When the collision is perfectly inelastic. Values between 0 and 1 describe partially inelastic collisions. Combined with momentum conservation, fully determines the final velocities.