| A | B |
|---|
| force | A push or a pull that acts on an object |
| newton | The SI unit of force |
| net force | The overall force acting on an object after all the forces are combined |
| friction | A force that opposes the motion of objects that touch as they move past each other |
| static friction | A friction force that acts on objects that are not moving |
| sliding friction | A friction force that opposes the motion of an object as it slides over a surface |
| rolling friction | A friction force that acts on rolling objects, caused by the change in shape at the point of rolling contact |
| fluid friction | A friction force that opposes the motion of an object through a fluid |
| air resistance | Fluid friction acting on an object moving through the air |
| gravity | The attraction between any two objects because of their masses |
| terminal velocity | The constant velocity of a falling object when the force of air resistance equals the force of gravity |
| projectile motion | The curved path of an object in free fall after it is given an initial forward velocity |
| inertia | The tendency of an object to resist a change in its motion |
| mass | The amount of matter in an object |
| weight | The force of gravity acting on an object |
| momentum | The product of an object's mass and its velocity |
| law of conservation of momentum | Law stating that the total momentum of a system does not change if no net force acts on the system |
| electromagnetic force | A force associated with charged particles, which has two aspects: electric force and magnetic force |
| strong nuclear force | The powerful attractive force that binds protons and neutrons together in the nucleus |
| weak nuclear force | A powerful attractive force that acts over a short range |
| gravitational force | An attractive force that acts between any two objects |
| centripetal force | A force that continuously changes the direction of an object to make it move in a circle |
