| A | B |
|---|
| Motion | when an objects distance is changing relative to another object |
| reference point | a place or object used for comparison to determine if something is in motion |
| SI | unit of measurments that scientists use. |
| meter | the SI unit for length |
| speed | the distance an object travels in a unit of time |
| velocity | speed and direction |
| acceleration | any change in velocity |
| meters per second per second | the unit used to describe acceleration |
| force | a push or pull |
| net force | all the forces added together |
| unbalanced force | a net force that changes an objects motion |
| balanced force | a net force of zero--it does not change an objects motion |
| inertia | an objects resistance to a change in motion |
| mass | the amount of matter an object has |
| Newton's first law of motion | an object at rest will stay at rest, and an object in motion will stay in motion unless acted upon by an unbalanced force |
| Newton's second law of motion | force=mass x acceleration |
| newton | the unit used to measure a force |
| friction | the force one object exerts on another when they rub together |
| sliding friction | when solid surfaces slide over each other |
| rolling friction | type of friction when an object rolls over a surface |
| fluid friction | type of friction when an object moves through a fluid |
| gravity | the force that pulls objects towards earth |
| projectile | an object that is thrown |
| air resistance | type of fluid resistance when objects move through air |
| terminal velocity | the maximum speed a falling object can reach |
| weight | the force of gravity on a person or object at the surface of a planet |
| momentum | the product of an object's mass and velocity |
| law of conservation of momentum | states that the total momentum of the objects that interact does not change |
| law of universal gravitation | states that the force of gravity acts between all objects in the universe |
| Newton's third law of motion | for every action there is an opposite and equal reaction. |
