##
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
** | *x*_{cm} = *m*_{n}*x*_{n} |

**
Velocity of the center of mass of a system of particles
** | *v*_{cm} = *m*_{n}*v*_{n} |

**
Acceleration of the center of mass of a system of particles
** | *a*_{cm} = *m*_{n}*a*_{n} |

**
Acceleration of the center of mass of a system of particles given an external
force
** | *F*_{ext} = *Ma*_{cm} |

**
Definition of Impulse
** | *J* = *FΔt* |

**
Change in velocity caused by an impulse
** | *J* = *mv*_{f} - *mv*_{o} |

**
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* = *Mv*_{cm} |