We explain what potential energy is, the different types of potential energy that exist and some examples of this mechanical energy.
What is potential energy?
Potential energy is a type of mechanical energy , which is associated with the relationship between a body and an external force field or system (if the object is located in the field) or internal (if the field is within the object). It is, so to speak, of potential energy, that is, it can be immediately transformed into other forms of energy , such as kinetics, for example.
The potential energy of a system, whatever its origin, represents the energy “stored” in it given its configuration or position, and therefore a reference point or configuration must be taken into account to measure it.
The concept of potential energy is useful for both conservative (which tend to preserve energy) and dissipative (which tend to lose it) physical systems, for which it must add to the kinetic energy of the system: this sum serves to give the total energy mechanics of it:
Potential energy + kinetic energy = total mechanical energy
This type of energy is studied not only by classical mechanics, but also relativistic mechanics and quantum physics, applying it to particle systems . The potential energy can be classified according to the forces that give rise to gravitational, elastic, chemical, among others.
Gravitational potential energy
This type of potential energy is defined based on the gravitational attraction of the Earth , or between masses of different magnitude located one in the proximity of the other. These masses can be that of the Sun and the planets that orbit it, or that of a roller coaster car when it reaches the top of the top.
In this last example, the potential energy that gravitational land attraction accumulates in the car that reaches the top is the greatest possible in its planned route, and then is transformed into kinetic energy by releasing the car in its fall down the rails. At that point of maximum energy accumulation its speed will be 0 and there will be no movement .
Elastic potential energy
The elastic potential energy has to do with the property of the elasticity of matter , which is the tendency to recover its initial form abruptly after having been subjected to deformation forces greater than its resistance. This abrupt movement is the one that operates in the springs, which are compressed and decompressed, or gives meaning to ancient war armaments such as catapults, or arcs that shoot arrows.
In this last example, the potential elastic energy reaches its maximum level as the arc tightens when pulling the elastic fiber, slightly bending the wood, but with speed = 0 still. The next moment the potential energy becomes kinetic and the arrow is thrown forward at full speed.
Chemical potential energy
In the case of chemical potential energy, we refer to the way in which atoms and molecules are structured in chemical bonds capable of storing energy, just as occurs in the body of animals with glucose, the compound from which we obtain the energy to fuel our metabolism .
The latter occurs from the oxidation of the glucose molecule , whose bonds, when broken, release the chemical potential energy that was in them. The same happens, for example, with the fossil fuel (hydrocarbons) in the car’s gas tank, before being subjected to combustion in the engine that will convert its potential chemical energy into kinetic energy to start the vehicle.
Electrostatic potential energy
In terms of electricity, the concept of potential energy also applies, especially when talking about electrical circuits (in which electricity is preserved) or methods of storing the current , which can then be converted into other forms of energy, such as the kinetic, thermal or light, given the enormous versatility of electricity.
The electrical potential is in fact calculated through electrostatic potential energy, which can be repulsive (if the charges are equal) or attractive (if they are of a different sign), thus giving rise to positive or negative potential energy, as the case may be.