peconse

peconse - Potential energy and conservation of energy THIS...

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Potential energy and conservation of energy THIS LECTURE IS ONE OF THE MOST IMPORTANT OF THE SEMESTER! Potential Energy We have seen that when a force does work on a system the system may acquire motion energy, i.e. kinetic energy . However, another possibility is the work simply stores the energy in the system without any change in kinetic energy. This stored energy is called potential energy . The logic is: F → r → W → energy (kinetic or potential or both) Potential energy is the energy stored in a system due to the position of the parts of the system. In short, potential energy is position energy . Mathematically, we stipulate that the work serves to increase the potential (stored) energy and write x 2 U = U(x 2 ) – U(x 1 ) - W = - F(x) dx x 1 by Fund. Thm. Calc. F(x) = - dU/dx . The reason for the minus sign will become evident later.
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Comment: Only the change in potential matters because the work always refers to a change in position and not just one position. Two special cases:
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peconse - Potential energy and conservation of energy THIS...

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