what do the various forms of energy have in common
Energy In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object.[note 1] Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The SI unit of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of 1 metre against a force of 1 newton.
Energy in the United States The majority of this energy is derived from fossil fuels: in 2010, data showed 25% of the nation's energy came from petroleum, 22% from coal, and 22% from natural gas. Nuclear power supplied 8.4% and renewable energy supplied 8%,[5] which was mainly from hydroelectric dams and biomass but also included other renewable sources such as wind power, geothermal and solar energy.[6] As of 2006, energy consumption had increased at a faster rate than domestic energy production over the last fifty years in the U.S. (when they were roughly equal). This difference was largely met through imports.[7]