| Term | Definition |
|---|---|
| What determines gravity? | the strength of the force of gravity between two objects depends on two factors: the masses objects and the distance between them |
| Force | push or pull |
| Gravity | attracts all objects toward each other |
| Law of Universal Gravitation | states that every object in the universe attracts every other object |
| Mass | amount of matter in an object |
| Weight | measure of the force of gravity on an object |
| Force of gravity decreases | as the distance increases |
| What keeps objects in orbit? | newton concluded that inertia and gravity combine to keep earth in orbit around the sun and moon in orbit around earth |
| Inertia | the tendency of and object to resist change in motion more mass = greater inertia |
| Newton's 1st law of motion | says that objects at rest will stay at rest and objects in motion will stay in motion with a constant speed and direction unless acted upon by a force |
