| A | B |
|---|
| Energy | The ability to do work or make change happen |
| kinetic energy | the energy of motion; kinetic energy depends on speed and mass |
| potential energy | the energy of position or condition (shape), stored energy |
| mechanical energy | the total energy of motion and position of an object |
| energy conversion | a change from one form of energy into another; any form of energy can be converted into any other form of energy |
| friction | a force that opposes motion between two surfaces that are touching |
| law of conservation of energy | the law that states that energy is neither created or destroyed |
| energy resource | a natural resource that cannot be converted by humans into other forms of energy |
| nonrenewable resources | natural resources that cannot be replaced or that can be replaced only over thousands or millions of years |
| fossil fuels | nonrenewable energy resources that form in the Earth's crust over millions of years from the buried remains of once - living organisms |
| renewable resources | natural resources that can be used and replaced over a relatively short time. |
