| A | B |
|---|
| astronomical unit | a unit of measurement equal to the distance form Earth to Sun |
| metric system | a system of measurement based on a few defined units (such as the meter) and in which larger and smaller units are related by powers of 10 |
| speed | the distance traveled in a certain amount of time; rate of movement |
| velocity | the rate of motion in a particular direction |
| acceleration | the rate at which velocity changes over time |
| deceleration | a decrease in speed over time |
| force | a push or pull |
| gravity | the force that pulls objects toward Earth; also, the attractive force exerted by a body or object on other bodies or objects |
| mass | the amount of matter in an object |
| matter | anything that has mass and takes up space |
| weight | a measure of the force of gravity on an object |
