| A | B |
|---|
| energy | the ability to do work |
| kinetic energy | the energy of motion; kinetic energy depends on speed and mass |
| gravitational potential energy | energy due to an object's position above the Earth's surface |
| potential energy | the energy of position or shape |
| mechanical energy | the total energy of motion and position of an object |
| chemical energy | the energy of a compound that changes as its atoms are rearranged to form a new compound; chemical energy is a form of potential energy |
| thermal energy | the total energy of the particles that make up an object |
| electrical energy | the energy of electric charges |
| light energy | the energy produced by the vibrations of electrically charged particles |
| sound energy | the energy caused by an object's vibration |
| nuclear energy | the form of energy associated with changes in the nucleus of an atom |
| energy conservation | a change from one form of energy into another |
| positive acceleration | acceleration in which velocity increases |
| energy efficiency | a comparison of the amount of energy before a conversion and the amount of useful energy after a conversion |
| 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 nor destroyed |
| perpetual motion machine | a machine that runs forever without any additional energy input; perpetual machines are impossible to create |
| energy resource | a natural resource that can be converted by humans into other forms of energy in order to do useful work |
| fossil fuels | nonrenewable energy resources that form in the Earth's crust over millions of years from the buried remains of once-living organisms |
| nonrenewable resource | a natural resource that cannot be replaced or that can be replaced only over thousands or millions of years |
| nuclear fission | the process in which a large nucleus splits into smaller nuclei |
| renewable resource | a natural resource that can be used and replaced over a relatively short time |
| biomass | organic matter, such as plants, wood, and waste, that contains stored energy |
| geothermal energy | energy resulting from the heating of the Earth's crust |
