Acceleration – The rate at which velocity changes (how quickly an object speeds up or slows down).
Equilibrium – An object under equal but opposite forces.
Force – Any push or pull on an object.
Free Fall – The movement of an object toward earth because of gravity.
Friction – A force that opposes motion of objects that touch as they move past each other.
Gravity – The attraction between two objects because of their masses.
Inertia – The tendency of an object to resist motion. More mass equals more inertia.
Mass – The amount of matter in an object.
Newton – Unit of force (N), 1N = 1 kg * m/s2
Velocity – The speed and direction an object is moving.
Weight – The force of gravity acting on an object.