Conservation of Momentum Glossary

A laboratory device that measures a projectile's speed by embedding it in a hanging block (perfectly inelastic collision) and measuring the resulting swing height. Combines momentum conservation with energy conservation.

The mass-weighted average position of all parts of a system. In a closed system, the center of mass velocity remains constant regardless of internal forces between the parts.

A system in which no net external force acts on the objects involved. Internal forces between objects within the system do not change the total momentum.

A fundamental principle stating that a particular physical quantity remains constant in a closed system. Momentum conservation holds when no net external force acts on the system.

A collision in which both total momentum and total kinetic energy are conserved. Objects bounce apart with no energy lost to deformation, heat, or sound.

The product of a net force and the time interval over which it acts, J = F * delta_t. Equal to the change in momentum of the object on which the force acts.

A collision in which total momentum is conserved but total kinetic energy is not. Some kinetic energy converts to other forms such as thermal energy and sound.

The energy of motion, KE = (1/2)mv^2. Unlike momentum, kinetic energy is a scalar (no direction) and is not conserved in inelastic collisions.

The product of an object's mass and velocity, p = mv. A vector quantity measured in kg m/s that describes the quantity of motion an object possesses.

For every action force there is an equal and opposite reaction force. This law is the foundation of momentum conservation: internal forces always come in equal-and-opposite pairs, so they cancel in the total.

A special inelastic collision in which the colliding objects stick together after impact, moving as a single combined mass. This type loses the maximum kinetic energy while still conserving momentum.

The backward motion of an object after it propels another object forward. Governed by conservation of momentum: the recoiling object gains momentum equal in magnitude and opposite in direction to the launched object.