Energy
- energy is the quantitativeproperty that must be transferred to an object in order to perform work on or to heat the object
- energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed
- radiation is the transmission of energy
Energy - Measurement
The SI unit of energy is the joule:
- joule is the energy transferred to an object by the work of moving it a distance of 1 meter against a force of 1 newton.
- joule = kg m2 s−2
Energy - Forms
common forms of energy include:
- kinetic energy of a moving object
- potential energy stored by an object’s position in a force field (gravitational, electric, or magnetic)
- elastic energy stored by stretching solid objects
- chemical energy released when fuel burns
- radiant energy carried by light
- thermal energy due to an object’s temperature
- etc
Energy - Mass Relation
Mass and energy are closely related. Due to mass–energy equivalence, any object that has mass when stationary (called rest mass) also has an equivalent amount of energy whose form is called rest energy, and any additional energy (of any form) acquired by the object above that resting energy will increase the object’s total mass just as it increases its total energy. For example, after heating an object, its increase in energy could be measured as a small increase in mass, with a sensitive enough scale