# Linear Momentum: Collisions

## Terms and Formulae

### Terms

Collision  -  The brief direct contact between two bodies that results in a net impulse on each body.
Elastic Collision  -  Any collision in which kinetic energy is conserved.
Inelastic Collision  -  Any collision in which kinetic energy is not conserved.
Completely Inelastic Collision  -  Any collision in which the two bodies stick together.

### Formulae

 Position of the center of mass of a system of particles xcm =  mnxn

 Velocity of the center of mass of a system of particles vcm =  mnvn

 Acceleration of the center of mass of a system of particles acm =  mnan

 Acceleration of the center of mass of a system of particles given an external force Fext = Macm

 Definition of Impulse J = FΔt

 Change in velocity caused by an impulse J = mvf - mvo

 Definition of momentum p = mv

 Relation between force and momentum = F

 Impulse-Momentum Theorem J = Δp

 Definition of the linear momentum of a system of particles P = Mvcm