Conservation laws in mechanics

In educational institutions, wise teachers tell their students that there is a law of conservation in mechanics. Its meaning lies in the fact that energy in a closed system can not irrevocably disappear, wasted on the performance of any work. In such processes, there is not a disappearance, but a transformation of energy of one kind into another. For example: click the switch - and the electric light flashes brightly. The meter regularly calculates the energy expended. Where does it disappear? Everything is simple: the electric current does work, while the energy is converted into radiation and heating. In other words, the conservation laws in mechanics are relevant for any mechanical device (or even electrical one - the difference is only in a kind of primordial energy and the name of the same phenomenon). In fact, the law of conservation is a fundamental principle, according to which the entire universe lives.

First of all, it is necessary to determine what is the kinetic and potential energy. Simply put, the first is the energy of the body movement, which characterizes the work performed by the body. And the second is the temporarily unrealized energy of the system of bodies, determined by the nature of the interaction and the location of objects in the system itself. It is only natural that the term originated from the Latin word meaning "opportunity". In mechanics, these two kinds of energy are transformed one into another.

The conservation laws in mechanics work as follows. For example, an object thrown upwards at the moment of obtaining a pulse has the maximum value of the kinetic energy. Accordingly, the speed of its movement is the highest at the initial moment. Gradually, it decreases, because the kinetic energy is converted into a potential one. As a result, the subject slows down and stops. This means that all of its stock of the original pulse energy has been transformed into a potential energy and accumulated in the system. Further, due to gravitational action, the object begins to fall. The potential energy is converted back to kinetic. It is not difficult to guess that at the initial moment of motion the velocity is minimal, but it gradually increases, since the value of the kinetic energy of the system increases. It is worth noting that in this case, despite the influence of the Earth's magnetic field (additional pulse), the total sum of the energies of the system remains unchanged.

To better understand conservation laws in mechanics, it makes sense to turn to your own life experience. Surely, as a child, everyone dropped a small but massive ball or an ordinary ball onto the metal base. At the same time he jumped up and fell again. This was repeated until the movement spontaneously ceased. But what about the law of conservation of energy in mechanics? After all, logically, the potential energy of the falling ball must be fully transformed into kinetic, and vice versa. Almost "perpetual motion". Is it possible that in this case the conservation laws in mechanics are not satisfied? In fact, in this situation, the system is affected by friction about air molecules and internal deformations of the surface and ball. It is they who "steal" their part of the energy, because of what the ball gradually ceases to bounce (by the way, therefore, it is impossible to create a perpetual motion within the framework of classical mechanics).

The universality of the conservation laws allows us to use them not only in calculations of the interaction of the systems of the macrocosm, but also, partially, in the microcosm. Neither the trajectory of the movement, nor the type of forces acting on the system, affects the result-conservation laws work!