the rate at which velocity changes; an object accelerates if its speed and / or direction changes. Acceleration may be postitive(increasing) or negative (decreasing)

1an object in motion will remain in motion or an object at rest will remain at rest unless acted upon by an outside force.
2the accelaration of an object is equal to the mass of that object and the force applied
3 for every action force there is an equal and opposite reaction force.

the action that results form doing something (W=fxd) Work =force times distance
work is equal to the force applied multiplied by the distance an object is moved

the total momentum of the two objects before the collsion is equal to the total momentum of the two objects after the collsion . That is, the momentum lost by object 1 is equal to the momentum gained by object 2