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Khalid Alhumaidhi

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Energy of a System

We recognize energy through the concepts of force and motion. When work is done on an object, it gains energy. Energy is made of two types, potential energy which is stored energy and kinetic energy, which consists of moving energy. Food is stored energy. It is stored as a chemical with potential energy. When your body uses that stored energy to do work, it then becomes kinetic energy.

Energy in a system may be transformed so that it resides in a different state. Energy in many states may be used to do many varieties of physical work. Energy may be used in natural processes or machines, or else to provide some service to society (such as heat, light, or motion). For example, an internal combustion engine converts the potential chemical energy in gasoline and oxygen into heat, which is then transformed into the propulsive energy (kinetic energy that moves a vehicle) (Ross, 2011). A solar cell converts solar radiation into electrical energy that can then be used to light a bulb or power a computer.

Any form of energy can be converted to another form. Most technological devices that we use are recognized as energy converters. Energy cannot be created, nor destroyed. This is the reason why it exists in many forms. For example, a light bulb converts electrical energy to radiant energy. It can come in various forms, mechanical, chemical, radiant, electrical, and nuclear.

Thermodynamics is the study of energy being converted from one form to another. There are three laws of thermodynamics. The first law states that energy cannot be created or destroyed, but it can be converted from one form to another. The second law states that heat energy can be transferred only from body at high temperature to the body at lower temperature. Heat can only be moved from high to low without external work being performed. If you want to move the heat energy from low temperature reservoir to high temperature reservoir, then something external must intercept in order for that to work. For instance, an air conditioner or a refrigerator heat moved to low temperature to high temperature, needing electricity to work or perform properly (Ross, 2011). Finally, the last law of thermodynamics states that all molecular movement stops at the temperature of absolute zero or 0 Kelvin.