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In physics, energy is a physical property of an object, can move through the fundamental interactions, which can be transformed but can not be created nor destroyed. Joule is the SI unit for energy, taken from the amount given to an object (via mechanical work) to move a distance of 1 meter with a force of 1 newton.
Work and heat are 2 examples of a process or mechanism that can move the amount of energy. The second law of thermodynamics limits the amount of work obtained through the heating process-some of which will be lost as waste heat. The maximum amount that can be used for energy is called the work available. Systems such as machines and living things need energy available, not just any energy. Mechanical energy and other forms of energy can be transferred directly into the form of heat energy without certain restrictions.
There are various forms of energy, but all energy types must meet various conditions can be converted into other forms of energy, obey the law of conservation of energy, and cause changes in body mass were subjected to the energy. Common forms of energy include kinetic energy of a moving object, the radiation energy of light and electromagnetic radiation, potential energy stored in an object due to its position as the gravitational field, electric field or magnetic field, and the heat energy consists of potential and kinetic energy of the microscopic movements of irregular particles. Some of the specific form of elastic potential energy is the energy resulting from elongation or deformation of solid objects and the release of chemical energy as heat when fuel is burned. Every object that has mass when stationary, have a rest mass or energy equal to the rest, though not described in the everyday phenomena in classical physics.
According to the mass-energy balance, all forms of mass requires energy. For example, adding a 25 kilowatt-hour (90 megajoules) of energy on an object will increase its mass by 1 microgram; if there are scales as good as they are sensitive then the addition of this mass could be seen. The sun converts energy nuclear potential into other forms of energy; total mass will change when the energy released into the surroundings, especially in the form of radiant energy.
Although energy can change forms, but the law of conservation of energy states that the total energy in a system is only changed if the energy moves into or out of the system. This means it is impossible to create or destroy energy. The total energy of a system can be calculated by adding all forms of energy in the system. Examples of transfer and transformation of energy is electricity generation, chemical reaction, or raise objects.
Living organisms also requires available energy to stay alive; humans, for example, require energy from food as well as oxygen to metabolizes it. Civilization requires a supply of energy for a variety of activities; energy sources such as fossil fuels is an important topic in economics and politics. Earth's climate and ecosystems are also run by the radiation energy obtained from the sun (as well as geothermal energy derived from the earth.
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