اقتباسات من كتب فرنسيس أور
فرنسيس أور
له (2) كتاب بالمكتبة, بإجمالي تحميل وقراءة (20,101)
غير متوفر وصف له.
"Energetic" redirects here. For other uses, see Energetic (disambiguation).
Energy
Sun in February (black version).jpg
The Sun is the source of energy for most of life on Earth. It derives its energy mainly from nuclear fusion in its core, converting mass to energy as protons are combined to form helium. This energy is transported to the sun's surface then released into space mainly in the form of radiant (light) energy.
Common symbols
E
SI unit joule
Other units
kW⋅h, BTU, calorie, eV, erg, foot-pound
In SI base units J = kg m2 s−2
Extensive? yes
Conserved? yes
Dimension M L2 T−2
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.
Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object's position in a force field (gravitational, electric or magnetic), the elastic energy stored by stretching solid objects, the chemical energy released when a fuel burns, the radiant energy carried by light, and the thermal energy due to an object's temperature.
Mass and energy are closely related
Mahy Ayman 