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The minimum total potential energy principle is a fundamental concept used in physics, chemistry, biology, and engineering. It asserts that a structure or body shall deform or displace to a position that minimizes the total potential energy, with the lost potential energy being dissipated as heat. For example, a marble placed in a bowl will move to the bottom and rest there, and similarly, a tree branch laden with snow will bend to a lower position. The lower position is the position for minimum potential energy: it is the stable configuration for equilibrium. The principle has many applications in structural analysis and solid mechanics. A binding energy is the energy that must be exported from a system for the system to enter a bound state. If the potential energy is chosen to be zero when the system is unbound, the potential energy of the system is negative after it enters a bound state.〔(Why is the Potential Energy Negative? ) ''HyperPhysics''〕 A bound system has a lower (''i.e.'', more negative) potential energy than the sum of its parts—this is what keeps the system aggregated in accordance with the minimum total potential energy principle. ==Some examples== * A free proton and free electron will tend to combine to form the lowest energy state (the ground state) of a hydrogen atom, the most stable configuration. This is because that state's energy is 13.6 electron volts (eV) lower than when the two particles separated by an infinite distance. The dissipation in this system takes the form of spontaneous emission of electromagnetic radiation, which increases the entropy of the surroundings. * A rolling ball will end up stationary at the bottom of a hill, the point of minimum potential energy. The reason is that as it rolls downward under the influence of gravity, friction produced by its motion transfers energy in the form of heat of the surroundings with an attendant increase in entropy. * A protein folds into the state of lowest potential energy. In this case, the dissipation takes the form of vibration of atoms within or adjacent to the protein. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Minimum total potential energy principle」の詳細全文を読む スポンサード リンク
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