What is called mechanical movement: definition and formula

From school, everyone probably remembers what is called mechanical body movement. If not, then in this article we will try not only to recall this term, but also to update the basic knowledge from the course of physics, or rather from the section "Classical Mechanics". Examples will also be shown that this concept is used not only in a certain discipline, but also in other sciences.

Mechanics

First, let’s analyze what this concept means. Mechanics is a section in physics that studies the motion of various bodies, the interaction between them, and the effect of third forces and phenomena on these bodies. The movement of a car along the highway, kicked by a kick to the goal with a soccer ball, a landing plane — all this is studied by this discipline. Usually, when using the term "Mechanics", they mean "Classical Mechanics". What is it, we will deal with you below.

Classical mechanics is divided into three large sections.

1. Kinematics - it studies the motion of bodies without considering the question of why they move? Here, such values ​​as path, trajectory, movement, speed are of interest.
2. The second section is dynamics. She studies the causes of the movement, in terms of such concepts as work, force, mass, pressure, momentum, energy.
3. And the third section, the smallest, is a static study of such a state as equilibrium. It is divided into two parts. One illuminates the balance of solids, and the second - liquids and gases.

Very often, classical mechanics is called Newtonian, because it is based on the three laws of Newton.

Newton's Three Laws

They were first set forth by Isaac Newton in 1687.

1. The first law states the inertia of the body. This property, in which the direction and speed of the motion of the material point is preserved, if no external forces act on it.
2. The second law states that the body, gaining acceleration, coincides with this acceleration in direction, but becomes dependent on its mass.
3. The third law states that the strength of an action is always equal to the strength of a reaction.

All three laws are axioms. In other words, these are postulates that do not require proof.

What is called mechanical movement

This is a change in the position of a body in space, relative to other bodies over time. Material points in this case interact according to the laws of mechanics.

It is divided into several types:

• The motion of a material point is measured by finding its coordinates and tracking coordinate changes over time. To find these indicators means to calculate the values ​​along the abscissa and ordinates. The kinematics of a point, which operates with such concepts as trajectory, displacement, acceleration, and speed, is engaged in the study of this. The movement of the object in this case can be rectilinear and curvilinear.
• The motion of a solid body is the sum of the displacement of some point taken as the basis, and the rotational motion around it. Studied by the kinematics of solids. The movement can be translational, that is, rotation around a given point does not occur, and the whole body moves uniformly, and also flat - if the whole body moves parallel to the plane.
• There is also movement of a continuous medium. This is the movement of a large number of points connected only by any field or area. In view of the multitude of moving bodies (or material points), one coordinate system is not enough here. Therefore, how many bodies, so many coordinate systems. An example of this is a wave at sea. It is continuous, but consists of a large number of individual points on a variety of coordinate systems. So it turns out that the movement of the wave is the movement of a continuous medium.

Movement relativity

There is also such a concept in mechanics as the relativity of motion. This is the influence of a reference system on mechanical motion. What does it mean? A reference system is a coordinate system plus a clock to determine the time. Simply put, these are abscissa and ordinates in combination with minutes. Through such a system, it is determined for what period of time the material point has traveled a given distance. In other words, it has moved relative to the coordinate axis or other bodies.

Reference systems can be: concomitant, inertial and non-inertial. Let us explain:

• Inertial CO is a system where bodies, producing what is called the mechanical movement of a material point, do this in a straightforward and uniform way or are generally at rest.
• Accordingly, non-inertial CO is a system that moves with acceleration or rotates with respect to the first CO.
• The accompanying CO is a system that, together with the material point, performs what is called the mechanical movement of the body. In other words, where and at what speed the object moves, this SO moves with it.

Material point

Why is the concept of "body" sometimes used, and sometimes the "material point"? The second case is indicated when the size of the object itself can be neglected. That is, such parameters as mass, volume, etc. are not important for solving the arisen problem. For example, if the goal is to find out how fast the pedestrian is moving relative to planet Earth, then the height and weight of the pedestrian can be neglected. He is the material point. The mechanical movement of this object does not depend on its parameters.

Used concepts and values ​​of mechanical motion

In mechanics they operate with various quantities, with the help of which parameters are set, the condition of the problems is written and the solution is found. We list them.

• A change in the location of a body (or material point) relative to space (or a coordinate system) over time is called displacement. The mechanical movement of the body (material point), in fact, is a synonym for the concept of "movement". It's just that the second concept is used in kinematics, and the first is used in dynamics. The difference between these subsections was explained above.
• The trajectory is the line along which the body (material point) performs what is called mechanical movement. Its length is called the path.
• Speed ​​is the speed at which a material point (body) moves relative to a given reporting system. The definition of a reporting system was also given above.

Unknown quantities used to determine mechanical motion are found in problems using the formula: S = U * T, where "S" is the distance, "U" is the speed, and "T" is the time.

From the history

The very concept of "classical mechanics" appeared in antiquity, and this was prompted by construction that was developing rapidly. Archimedes formulated and described the rule of leverage, the theorem on the addition of parallel forces, introduced the concept of "center of gravity". So the statics conceived.

Thanks to Galileo, "Dynamics" began to develop in the 17th century. The law of inertia and the principle of relativity is his merit.

Isaac Newton, as mentioned above, introduced three laws that formed the basis of Newtonian mechanics. He also discovered the law of gravity. So the foundations of classical mechanics were laid.

Non-classical mechanics

With the development of physics as a science, and with the advent of great opportunities in the fields of astronomy, chemistry, mathematics, and other things, classical mechanics gradually became not the main, but one of the many demanded sciences. When they began to actively introduce and operate with such concepts as the speed of light, quantum field theory, and so on, the laws underlying the "Mechanics" became lacking.

Quantum mechanics is a branch of physics that deals with the study of ultra-small bodies (material points) in the form of atoms, molecules, electrons and photons. This discipline very well describes the properties of ultrafine particles. In addition, she predicts their behavior in a given situation, as well as depending on the impact. The predictions made by quantum mechanics can be very different from the assumptions of classical mechanics, since the second is not able to describe all the phenomena and processes that occur at the level of molecules, atoms and other things - very small and invisible to the naked eye.

Relativistic mechanics is a branch of physics that studies processes, phenomena, and laws at speeds comparable to the speed of light. All events studied by this discipline occur in four-dimensional space, in contrast to the "classical" - three-dimensional. That is, to the height, width and length we add another indicator - time.

What else is the definition of mechanical motion

We considered only basic concepts related to physics. But the term itself is used not only in mechanics, whether it be classical or non-classical.

In a science called "Socio-economic statistics" the definition of the mechanical movement of a population is given as migration. In other words, this is the movement of people over long distances, for example, to neighboring countries or to neighboring continents in order to change their place of residence. The reasons for this displacement may be the inability to continue to live on its territory due to natural disasters, for example, constant floods or drought, economic and social problems in its state, or the intervention of external forces, for example, war.

This article discusses what is called mechanical movement. Examples are given not only from physics, but also from other sciences. This indicates that the term is ambiguous.