1. 4 Types of Planetary Motion
Use your textbook to define the following words
Rotation-
Revolution-
Gravity-
Inertia-

2. Rotation- when an object spins on its axis, it causes day & night

3. Revolution- When an object goes around another object, to orbit, one trip around the sun is a year on that planet

4. Gravity- a force that pulls objects together, the mass and distance between objects affects its strength, it holds solar sys. and galaxies together
Inertia- an objects resistance to change in its speed or direction, a planets forward motion, when balanced with gravity it keeps planets orbiting, if not balanced the planet will travel off into space