| A | B |
|---|
| Motion | An object's change in position over time when compared with a reference point |
| Speed | The rate at which an object moves; speed depends on the distance traveled and the time taken to travel that distance |
| Velocity | The speed of an object in a particular direction |
| Acceleration | The rate at which velocity changes; an object accelerates if its speed changes, or if both its speed and its direction change |
| Force | A push or a pull; all forces have both size and direction |
| Newton | The SI unit of force |
| Net Force | The force that results from combining all the forces exerted on an object |
| Friction | A force that opposes motion between two surfaces that are touching |
| Gravity | A force of attraction between objects that is due to their masses |
| Weight | A measure of the gravitational force exerted on an object, usually by the Earth |
| Mass | The amount of matter that something is made of; its value does not change with the object's location |
| Vector Quantity | A measure of magnitude with direction. Velocity is an example. |
| Scalar Quantity | A measure of magnitude, or how much? |
| Terminal Velocity | The constant velocity of a falling object when the size of the upward force of air resistance mathces the size of the downward force of gravity |
| Free Fall | The condition an object is in when gravity is the only force acting on it |
| Projectile | The curved path an object follows when thrown or propelled near the surface of Earth |
| Inertia | the tendency of all objects to resist any change in motion |
| Momentum | A property of a moving object that depends on the obeject's mass and velocity |
