| A | B |
| force | a push or a pull |
| friction | the force caused by two objects rubbing together |
| gravity | the force that pulls objects toward the center of the earth |
| magnetism | the force that causes magnets to pull on objects that are made of certain metals |
| pole | a place on a magnet where magnetism is strongest |
| work | something done whenever a force moves through a distance |
| simple machine | one of the six kinds of tools with few or no moving parts that make work easier |
| lever | a simple machine made of a bar or board that is supported underneath at the fulcrum |
| fulcrum | the point on which a lever is supported and moves |
| inclined plane | a simple machine that is a flat surface with one end higher than the other |
| screw | a simple machine used to hold objects together |
| wedge | a simple machine used to cut or split an object |
| pulley | a simple machine made of a wheel and a rope |
| gear | a wheel with jagged edges like teeth |
| wheel and axle | a simple machine that has a cneter rod attached to a wheel |