The energy possessed by the body by virtue of its state is called potential energy.The term potential energy means ‘stored’ energy. A stretched bow-string possesses potential energy. When it is released, the arrow flies off at a great speed.
The earth’s crust is not uniform, but has discontinuities and dislocations that are called fault lines. These fault lines in the earth’s crust are like ‘compressed springs’. They possess a large amount of potential energy. An earthquake results when these fault lines readjust. Thus, potential energy is the ‘stored energy’ by virtue of the position or configuration of a body. The body left to itself releases this stored energy in the form of kinetic energy .
The gravitational force on a ball of mass m is mg . g may be treated as a constant near the earth surface. That means that height h of the ball above the earth’s surface is very small compared to the earth’s radius so that we can ignore the variation of g near the earth’s surface.
Let us take the upward direction to be positive. Let us raise the ball up to a height h. The work done by the external agency against the gravitational force is mgh. This work gets stored as potential energy. Gravitational potential energy of an object, as a function of the height h, is denoted by V(h) and it is the negative of work done by the gravitational force in raising the object to that height.
V (h) = mgh
If h is taken as a variable, it is easily seen that the gravitational force F equals the negative of the derivative of V(h) with respect to h. Thus,The negative sign indicates that the gravitational force is downward. When released, the ball comes down with an increasing speed. There fore the potential energy is there converted into kinetic energy.
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The earth’s crust is not uniform, but has discontinuities and dislocations that are called fault lines. These fault lines in the earth’s crust are like ‘compressed springs’. They possess a large amount of potential energy. An earthquake results when these fault lines readjust. Thus, potential energy is the ‘stored energy’ by virtue of the position or configuration of a body. The body left to itself releases this stored energy in the form of kinetic energy .
The gravitational force on a ball of mass m is mg . g may be treated as a constant near the earth surface. That means that height h of the ball above the earth’s surface is very small compared to the earth’s radius so that we can ignore the variation of g near the earth’s surface.
Let us take the upward direction to be positive. Let us raise the ball up to a height h. The work done by the external agency against the gravitational force is mgh. This work gets stored as potential energy. Gravitational potential energy of an object, as a function of the height h, is denoted by V(h) and it is the negative of work done by the gravitational force in raising the object to that height.
V (h) = mgh
If h is taken as a variable, it is easily seen that the gravitational force F equals the negative of the derivative of V(h) with respect to h. Thus,The negative sign indicates that the gravitational force is downward. When released, the ball comes down with an increasing speed. There fore the potential energy is there converted into kinetic energy.
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