| A | B |
|---|
| energy | the ability to do work |
| kinetic energy | the energy of motion; kinetic energy depends on speed and mass |
| potential energy | the energy of position of shape |
| mechanical energy | the total energy of motion and position of an object |
| enegy 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 nor destroyed |
| energy resource | a natural resource that can be converted by humans into other forms of energy in order to do useful work |
| nonrenewable resources | natural resources that cannot be replaces or that can be replaced only over thousands or milions 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 | natrual resources that can be used and replaced over relatively short time |
