| A | B |
|---|
| friction | a force that opposes motion between surfaces that are touching |
| fossil fuels | energy resources that formed from the buried remains of plants and animals that lived millions of years ago |
| kinetic | the energy of motion |
| nonrenewable | energy resources that cannot be reused after they are used |
| law of conservation of energy | this states that energy cannot be created or destroyed |
| closed system | a well-defined group of objects that transfer energy to one another |
| mechanical | kinds of energy that is the sum of kinetic and potential energy |
| gravitaional | potential energy dependent upon an object's weight and distance from Earth's surface |
| energy | the ability to do work |
| renewable | resources that can be used and replaced in nature over a relatively short period of time |
| potential | the energy of position |
| conversion | a change of one form of energy into another |
| nuclear energy | produced when two or more nuclei join together or when the nucleus of one atom splits apart |
| energy resource | a natural resource that can be converted by humans into other forms of energy in order to do useful work |
| energy efficiency | a comparison of the amount of energy before a conversion with the amount of useful energy after a conversion |
| aerodynamic | shape of a car that helps it be more energy efficient |
| geothermal energy | energy caused by the heating of the Earth's crust |
| electric generator | machine that converts chemical energy in fossil fuels into electric energy |
