Potential energy

As follows from the Law of conservation of energy, any body always has energy. In the presence of motion, this is obvious: there is a speed or acceleration, which, multiplied by the mass, gives the desired result. However, in the case when the body is motionless, it may, paradoxically, also be characterized as having energy.

So, the kinetic energy arises during the motion, the potential energy - with the interaction of several bodies. If everything is more or less obvious from the first, then often the force arising between two immovable objects remains beyond understanding.

It is well known that the planet Earth affects all the bodies that are on its surface due to the gravitational field. That is, it attracts any object with a certain force. When moving an object, changing its height, there is also a change in the energy indicators. Immediately at the moment of lifting, the body has acceleration. However, at its highest point, when the object (even for a split second) is immobile, it has potential energy. The thing is that he is still drawn to the field of the Earth, with which the desired body interacts.

In other words, the potential energy arises always due to the interaction of several objects forming the system, regardless of the size of the objects themselves. At the same time, by default one of them is represented by our planet.

Potential energy is a quantity that depends on the mass of the object and the height to which it is raised. The international designation is the Latin letters Ep. The formula for potential energy is as follows:

Ep = mgh,

Where m - mass, g - acceleration of gravity, h - height.

It is important to consider in more detail the altitude parameter, since it often causes difficulties in solving problems and understanding the value of the quantity under consideration. The fact is that any vertical movement of the body has its initial and final point. For a correct finding of the potential energy of the interaction of bodies, it is important to know the initial height. If it is not specified, then its value is zero, that is, it coincides with the Earth's surface. In the case, if both the starting point of reference and the final height are known, it is necessary to find the difference between them. The resulting number and becomes the desired h.

It is also important to note that the potential energy of the system can have a negative value. Suppose we have already lifted the body above the Earth's level, so it has a height, which we will call initial. When it is lowered, the formula will look like this:

Ep = mh (h2-h1).

Obviously, h1 is greater than h2, therefore, the value will be negative, which will give the whole formula a minus sign.

Curiously, the potential energy is higher, the farther from the surface of the Earth is the body. In order to better understand this fact, we will reflect: the higher it is to lift the body above the Earth, the more thoroughly the perfect work. The higher the value of the work of any force, the more, relatively speaking, the more energy is invested. Potential energy, in other words, is the energy of opportunity.

Similarly, it is possible to measure the energy of interaction of bodies when the object is stretched.

Within the framework of the topic under consideration, it is necessary to discuss separately the interaction of a charged particle and an electric field. In such a system, the potential energy of the charge will be present. Let us consider this fact in more detail. The same force acts on any charge located within the electric field. The movement of a particle is due to the work done by this force. Considering that the actual charge and the electromagnetic field (more precisely, the body that created it) is a system, we also get the potential energy of charge transfer within the given field. Since this type of energy is a special case, it was given the name of electrostatic.