| A | B |
|---|
| force | a push or pull one body exerts on another |
| balanced force | forces that are equal in size and opposite in direction which do not cause acceleration |
| mass | amount of matter in an object |
| friction | force that opposes motion between two surfaces that are touching each other |
| gravitational force | force exerted by every object in the universe on every other object |
| weight | measure of the force of gravity on an object |
| vector | arrow used to represent a force |
| free body diagram | 3-D representation of an object where all the forces are shown using vectors |
| equilibrium | occurs when the forces acting on an objectare balanced |
| nonequilibrium | occurs when the forces acting on an object are not balanced |
| newton | standard SI unit of force |
| spring scale | tool used for measuring force |
| gravity | acceleration due to gravitation force; 9.8 m/s2 on Earth |
| freefall | occurs when the only force acting on a moving object is gravitational force |
| air resistance | the opposing force creating by objects moving through air |
| terminal velocity | the greatest velocity that a falling object reaches |
| weightlessness | the false sense of being weightless that all falling objects experience |
| centripetal force | force caused by friction where the object's motion is directed towards the center of a curve |
| centripetal acceleration | change in direction of a moving object due to centripetal force |
| projectile | any object that is thrown or shot |
| air pressure | mechanical force caused by collisions of gas molecules |
| inertia | tendency of an object to resist any change in its motion |
| Newton's First Law of Motion | another name for inertia |
| Newton's Second Law of Motion | relates the acceleration that an object will experience to its mass and the force applied to it |
| Newton's Third Law of Motion | to every action there is an equal and opposite reaction (action-reaction pairs) |
| momentum | property of a moving object which is due to its size and velocity |
