What is the main task of mechanics?

In the development of natural science, the leading role was played by classical mechanics, or Newtonian mechanics, still plays. Within its framework there is an explanation of a variety of physical phenomena and processes occurring in terrestrial and extraterrestrial conditions. Many methods of scientific research are formed precisely on its basis. The essence of the mechanistic worldview prevailing in science practically up to the beginning of the twentieth century is reduced to the explanation of all physical processes by the motion and interaction of bodies and particles. That is, mechanics is the science of the motion of bodies.

Newton's concept, briefly expressed by Einstein, said: physical reality is determined by the factors of time, space, material point and force, that is, the interaction of material points. The main task of mechanics, thus, was reduced to the study of physical events, by which motion and interaction in the space of material points were understood, proceeding according to unchanging laws.

In modern interpretation, the field of application of classical mechanics is the interaction of bodies with a relatively slow motion (many times less than the speed of light). The "classical" concepts of space, time, force, mass, etc. remained unchanged, the basic laws of mechanics are and will not be refuted as long as science exists.

Let's recall the main concepts of mechanics. This mechanical movement is the so-called change in the position of a given body relative to other bodies in space and time (for example, the movement of a vehicle, an hour hand, a celestial body, a molecule), the relativity of motion-the body moves relative to one body and may be stationary relative to others . Example - the driver of the car is moving relative to pedestrians and is immobile relative to the body of the car. Therefore, there is the notion of the body of reference, the so-called body, about which the motion occurs.

The coordinate system determines the location of the body or point in space. Movement can occur in a straight line, in a plane or in space. Accordingly, one, two or three of its coordinates are changed. The main task of mechanics is to determine the coordinate of the body at a certain (any) moment. In this case, the coordinate is the distance from the reference point along the corresponding axis. In addition, it should be borne in mind that the motion is carried out in a certain time interval, i.e., time is also one of the initial values.

Thus, the frame of reference, in which the main task of mechanics is solved, is the coordinate system and the clock. Any movement does not happen by itself, but with respect to the chosen frame of reference. Knowing how the coordinate of the body changes with time, we can know the position of a given body (point) at any time that we need.

The main task of mechanics is, therefore, to determine the position of the body (its coordinates) at any point in time that we need.

Each body has its own specific dimensions. In the translational motion, all its points move along a single trajectory, and there is no need to describe the motion of all points. How to determine its coordinates? Under certain conditions (if the size of the body is many times less than the distance traveled by it) its dimensions can be neglected and the body can be considered a material point. For example, when the Earth moves in orbit, our planet can be mistaken for a material point. When studying the same processes that occur on the surface of the Earth, it can not be considered as such. That is, in mechanics, a material point is a body whose dimensions can be neglected.

A path is the distance that a point travels along a path. Movement - a vector (a directed segment), connecting the two positions of the body, the initial and final.

In addition, the movement is not always progressive. If the body parts move along different trajectories, such motion can be considered as a rotation around a certain axis. Any movement in mechanics is a set of translational and rotational motions.