| A | B |
|---|
| Chemical energy | energy that comes from chemical changes |
| Complex machine | a machine made of many simple and compound machines |
| Compound machine | a machine made of two or more simple machines |
| Electrical energy | energy that comes from the flow of electricity |
| Energy | the ability to do work |
| Force | a push or pull on an object that can cause it to change motion |
| Friction | a force that slows the motion of moving objects |
| Gravity | a force that pulls any two objects toward one another, such as you toward the center of the Earth |
| Inertia | the tendency of a moving object to stay in motion or a resting object to stay at rest |
| Kinetic energy | energy of motion |
| Mechanical energy | the kind of energy an object has because it can move or because it is moving |
| Potential energy | energy that an object has because of position |
| Simple machine | a machine made of one or two parts |
| Work | the result of a force moving an object |
