What is mechanical motion in physics definition. Causes of social movements

Movement is any change in general, starting with the spatial movement of objects and ending with human thinking. Movement is an attribute of matter, an integral property of any material object. There is no matter without motion, and vice versa. Movement is an abstraction, abstracted by our consciousness from real material objects, the property to change its parameters. Therefore, movement in its "pure form" exists only in thinking, in reality, there are only moving material objects. There cannot be an absolutely motionless material object. Rest is the opposite of movement (lack of movement). Any moving object is predetermined. time retains its qualitative certainty, the stability of the internal structure, that is, some constancy, immutability. This is an indispensable condition for the existence of any thing. That. -movement and rest are dialectically contradictory properties of a material object. Development is an irreversible qualitative change. It can be progressive - resulting from an increase in the complexity and orderliness of the object, and regressive - the degradation of the object, its decay, death. Engels identified 5 main forms of movement:

• 1. Mechanical
• 2. Physical
• 3. Chemical
• 4. Biological
• 5. Social

All these forms of movement are interconnected and simpler ones are included in more complex ones, forming a qualitatively different form of movement. Each of these forms includes an infinite number of types of movement. Even, according to Engels, the simplest mechanical movement includes such types of motion as uniformly rectilinear, uniformly accelerated (slow), curvilinear, chaotic, etc.

The most complex form of movement is social, since the material carrier is the most complex type of matter - social. This form of movement also includes changes that occur in the body of an individual. So, the human heart is a mechanical engine that ensures the movement of blood in the vessels. But this is not a purely mechanical engine. Its activity is regulated by the mechanisms of higher nervous activity of a person. And the vital activity of the organism is a condition for the participation of a person in labor, in public life. This includes changes social groups, layers, classes, ethnic changes, demographic processes, development productive forces and production relations and other changes determined by the laws of motion at the social level of matter.

It should be emphasized that various forms motions are capable of passing into each other in accordance with the laws of conservation of matter and motion. This is a manifestation of the property of indestructibility and increatibility of matter and motion. The measure of motion of matter is energy, the measure of rest, inertia is mass.

Matter is an objective reality given to us in sensations. Matter is one of the most general categories of our thinking. It contains only the minimum number of signs of the designated object. The first step in specification matter i-i recognition of the complex organization of objective reality, in which material objects (things) are distinguishable, as well as their properties and relationships. The next step in concretizing the concept of matter is the attribution of some general attributive properties to all material objects. Properties: consistency (orderliness, structural certainty), activity (movement, change, development), self-organization, spatio-temporal form of being, reflection, informativeness. Structural levels of matter organization: First, by complexity, we define three large types of systems: systems of inanimate nature, biosystems and social systems. Further, inside each of these types of systems, we look for structural levels in inanimate nature - physical vacuum, particles, fields, atoms, molecules. In living nature - nucleic acids, proteins, cells, biocenoses. In the organization of social life, systems and subsystems of human action (material and spiritual production, politics, morality) are visible. Thus, the material world is a multi-tiered structure formed by the structural levels of matter.

The principle of determinism. Categories of cause and effect, necessity and chance, possibility and reality

Determinism - the doctrine of the objective regular relationship and interdependence of things, processes and phenomena of the real world. Determinism presupposes the existence of a variety of objective existing forms interrelations of phenomena, many of which are expressed in the form of ratios that do not have a directly causal character, i.e. not directly containing the moments of generation, production of one another. This includes spatial and temporal correlations, functional dependencies, symmetry relations, interaction of parts in systems of mutual determination of parts and the whole, connection of states in motion and development, etc.

Cause and investigation. When one phenomenon under certain conditions modifies or gives rise to another phenomenon, the first acts as a cause, the second - as a consequence. Causality is a connection that always brings to life something new that turns possibility into reality. The principle of causality is of great importance in scientific knowledge reality. The interaction of cause and effect is called the principle feedback, which operates in all self-organizing systems where information is perceived, stored, processed and used. The reasons are external and internal. The internal cause operates within the framework of this system, and the external cause characterizes the interaction of one cause with another. Objective causes are carried out in addition to the will and consciousness of people. Subjective reasons are contained in the purposeful actions of people, in their determination, organization, experience, knowledge. The immediate causes are those. directly call and define this action. Indirect - which cause and determine this action through a number of intermediate links.

Necessity and chance. Randomness is something that, under given conditions, may or may not be, it can happen this way, but it can happen otherwise. Randomness can be external and internal. An example of an external accident is a man stepped on a watermelon peel and fell. What is internal randomness? According to Darwin's theory, imperceptible random changes beneficial to them are fixed by heredity. In the surrounding world, both necessary and random events. Necessity is such a development of phenomena that inevitably follows from internal, essential properties, the relationship of these phenomena. Necessity is internal and external, i.e. generated by the object's own nature or confluence external circumstances. It can be characteristic of a set of objects or a single object. Chance is in manifold connections with necessity, by virtue of which necessity manifests itself in the form of chance, and the boundary between chance and necessity is never closed. However, the main direction of development determines precisely the need.

Possibility and reality. Reality is understood as the creative result of the action of all the real forces of the world: it is nature and The World History, man and his mind, material and spiritual culture, this is the unity of essence and phenomenon, internal and external, necessary and accidental, individual and general. D. is something that has already arisen, realized, that lives and acts. Possibility is the future in the present, it is something that does not exist in a given qualitative certainty, but that can arise and exist, become a reality under certain conditions. In time, possibility precedes reality. But reality, being the result of previous development, is at the same time the starting point further development. Possibility arises in the given reality and is realized in the new reality.

Motion- any change in general, starting with the spatial movement of objects and ending with human thinking. Movement is an attribute of matter, an integral property of any material object. There is no matter without motion, and vice versa. Movement is an abstraction, abstracted by our consciousness from real material objects, the property to change its parameters. Therefore, movement in its "pure form" exists only in thinking, in reality, there are only moving material objects. There cannot be an absolutely motionless material object. peace- opposite to movement (lack of movement). Any moving object is up to defined. time retains its qualitative certainty, the stability of the internal structure, that is, some constancy, immutability. This is an indispensable condition for the existence of any thing. That. movement and rest are dialectically contradictory properties of a material object.
Development- irreversible qualitative change. It can be progressive - resulting from an increase in the complexity and orderliness of the object, and regressive - the degradation of the object, its decay, death. Engels identified 5 main forms of movement:
1. Mechanical
2. Physical
3. Chemical
4. Biological
5. Social
All these forms of movement are interconnected and simpler ones are included in more complex ones, forming a qualitatively different form of movement. Each of these forms includes an infinite number of types of movement. Even, according to Engels, the simplest mechanical movement includes such types of motion as uniformly rectilinear, uniformly accelerated (slow), curvilinear, chaotic, etc.
The most complex form of movement is social, since the material carrier is the most complex type of matter - social. This form of movement also includes changes that occur in the body of an individual. So, the human heart is a mechanical engine that ensures the movement of blood in the vessels. But this is not a purely mechanical engine. Its activity is regulated by the mechanisms of higher nervous activity of a person. And the vital activity of the organism is a condition for the participation of a person in labor, in social life. This includes changes in social groups, strata, classes, ethnic changes, demographic processes, the development of productive forces and production relations, and other changes determined by the laws of motion at the social level of matter.
It should be emphasized that various forms of motion are capable of transforming into each other in accordance with the laws of conservation of matter and motion. This is a manifestation of the property of indestructibility and increatibility of matter and motion. The measure of motion of matter is energy, the measure of rest, inertia is mass.

38). The concept of space and time in philosophy. Modern scientific and philosophical ideas about space and time.

Space is a form of coordination of coexisting objects, states of matter. It lies in the fact that the objects are located outside each other (nearby, sideways, below, above, inside, behind, in front, etc.) and are in certain quantitative relationships. The order of coexistence of these objects and their states forms the structure of space.
Phenomena are characterized by the duration of existence, the sequence of stages of development. Processes are performed either simultaneously, or one earlier or later than the other; such, for example, are the relationships between day and night, winter and spring, summer and autumn. All this means that bodies exist and move in time. Time is a form of coordination of changing objects and their states. It lies in the fact that each state is a sequential link in the process and is in certain quantitative relations with other states. The order of change of these objects and states forms the structure of time.
Space and time- these are universal forms of existence, coordination of objects. The universality of these forms of being lies in the fact that they are the forms of being of all objects and processes that were, are and will be in the infinite world. Space and time have their own characteristics. Space has three dimensions: length, width and height, while time has only one - the direction from the past through the present to the future. It is inevitable, unique and irreversible.
In the history of philosophy, there have been various concepts of space and time. They can be divided into two large classes: the concepts of substance and relational. The substantial concept considers space and time as special entities that exist on their own, regardless of material objects. They are like an arena in which objects are located and processes are deployed. Just as an arena can exist without the fact that certain objects are placed on it, actors move, some kind of performance is played out, so space and time can exist independently of material objects and processes. In contrast to the substantial approach, the relational concept of space and time has developed in the history of philosophy. One of its most prominent representatives was G. V. Leibniz. He insisted that space and time are special relationships between objects and processes and do not exist outside of them.
Achievements modern science indicate the preference for a relational approach to understanding space and time. In this regard, first of all, it is necessary to single out the achievements of physics of the 20th century. The creation of the theory of relativity was that significant step in understanding the nature of space and time, which allows deepening, clarifying, concretizing philosophical ideas about space and time.
The special theory of relativity, the construction of which was completed by A. Einstein in 1905, proved that in the real physical world, spatial and temporal intervals change when moving from one frame of reference to another.
It turned out that only when the velocities of motion are small relative to the speed of light, one can approximately assume that the sizes of bodies and the course of time remain the same, but when we are talking about motions with velocities close to the speed of light, then the change in spatial and time intervals becomes noticeable. With an increase in the relative speed of the frame of reference, the spatial intervals are reduced, and the temporal ones are stretched.
The theory of relativity revealed one more essential side of the spatio-temporal relations of the material world. She revealed a deep connection between space and time, showing that in nature there is a single space-time, and separate space and separate time act as its original projections, into which it is split in different ways depending on the nature of the movement of bodies.
Thus, the philosophical conclusions from the special theory of relativity testify in favor of the relational consideration of space and time: although space and time are objective, their properties depend on the nature of the motion of matter, are associated with moving matter.

39). The concept of dialectics in the history of philosophy. Dialectics as a doctrine of universal connection and development.

Dialectics is theory and general method of cognition and transformation of reality. Dialectics in cognition does not replace special methods specific sciences, but is their common basis, acts as a way of reproducing in thinking the most general laws, properties and relations of objective reality. The elements of dialectics are its principles, categories and laws. Elements of dialectics can be inherent in various, including opposite, philosophical trends: materialism and idealism.
The opposite of the dialectical method is metaphysics(recall that this term is also used as a synonym for ontology or the concept of philosophy in general). The metaphysical method is characterized by an inclination to build an unambiguous and static picture of the world, a one-sided interpretation of phenomena, and a reduction (reduction) of the complex to the simple.
One of the basic principles of dialectics is the principle of universal connection. Connection- this is a state of interdependence of phenomena and processes, the dependence of some phenomena and processes on others in any respect. Everything in the world is interconnected. Relationships can be essential and non-essential, direct and indirect, internal and external, direct and reverse, etc.
The universal connection of phenomena in our time is recognized in almost all philosophical systems. The "new" metaphysics also recognizes the existence of a universal connection, but is characterized by a subjectivist snatching of individual aspects and properties of an object and their arbitrary mechanical connection. This is a simplified approach, a manifestation of eclecticism, that is, an unsystematic combination of various information and knowledge.
The most important attribute (an integral property) of being is movement, which includes all the processes taking place in the world. The philosophical understanding of motion covers any interaction of any objects. Motion is a change in general. Movement is absolute, universal, while rest is relative. So, a body resting on the surface of the Earth is in motion together with the Earth around the Sun, and together with solar system a body resting on the Earth moves around the center of the Galaxy, etc.
A special case of motion is development. In the course of development, the emergence of a fundamentally new, the transition of things and phenomena to a different qualitative state takes place. In the process of the formation of the new, the unity of the existing and the non-existent, of being and non-being finds a kind of reflection. The new arises on the basis of the old as the prerequisites and conditions for the transition from the old to the new develop.
Motion can be carried out both in ascending and descending branches. In the first case it will be a progressive development, and in the second it will be a regressive one.
Recall that matter is understood as the whole objective reality, which is given to a person in his sensations. Regular and diverse transitions from the old quality to the new lead to the fact that there are qualitatively different types objects and processes. The main types of movement and interaction of objects existing in the world are called forms of motion of matter. In accordance with the data of modern science, there are three main groups of motion forms matter: in inorganic nature, in living nature, in society. Taking into account the accepted classification of sciences, physical, chemical, biological and social forms of movement are usually considered.
The interconnection of all existing forms of movement testifies to the material unity of the world. As already noted, this relationship is characterized by a combination and complex interaction of progressive and regressive tendencies. The progressive trend of change implies an increase in the degree of organization of systems. In the most general form it manifests itself in the successive transition in the process of evolution of the Universe from physical to chemical, biological and social forms of motion. Such a sequence testifies to a certain direction of changes in the objective world, confirming the applicability of the principles of development to the world we observe as a whole.
Physical changes inherent in any objects of nature and, in the first approximation, can be specified through known types of interaction: electromagnetic, gravitational, strong (nuclear) and weak. The sources of interaction are respectively: electric charge, mass, light charge, weak charge. Electromagnetic and gravitational interactions have an infinite radius, strong and weak interactions appear only in the microcosm.
Chemical form motion occurs at a certain stage in the evolution of the Universe, when the genesis occurs chemical elements and various atomic-molecular structures arise. The process of synthesis of chemical elements in nature continues in our era. For example, red giant stars and so-called supernovae are real "factories for the production of elements."
The complication of chemical compounds and the emergence of highly organized supramolecular structures (chemical evolution) ensured a natural transition to a higher, life-related form of motion of matter - b i o l o g i c h e c o y. Life is realized in individual organisms and in their aggregates (populations, species, etc.). According to genetics, environmental influences (for example, radioactive or ultraviolet radiation) lead to mutations and may be accompanied by the appearance of qualitatively new organisms. Due to natural selection, the organisms most adapted to the conditions of their environment survive and give rise to new biological species.
At the pinnacle of biological evolution are the higher apes. The closest human ancestors, Australopithecus, several million years ago switched to a terrestrial way of life and the use of natural objects as tools. The systematic use of tools was accompanied by the beginnings of social production, and later labor activity created the prerequisites for the emergence of consciousness and speech. The process of the formation of man and society led to the emergence of a social form of the movement of matter.
Evolutionary changes in society, that is, an increase or decrease in what exists, prepare revolutionary processes - the emergence of a qualitatively new one. Evolutionary and revolutionary processes are dialectically interconnected. The new cannot come from nothing. The new is the result of development on the basis of the old, existing, although it is not its repetition in the main and basic. There is a dialectical negation here, which will be discussed below.
The higher forms of movement include the lower forms in a transformed form. At the same time, the higher forms of movement are irreducible to the lower ones. Thus, the phenomena of life cannot be fully explained and predicted based on the laws that describe physical and chemical processes. In the same way, the social is not reduced to the natural. For example, morality, love, patriotism, etc. cannot be explained in terms of anatomy, physiology, genotype, or any other biological characteristics of a person.

mechanical movement

Mechanical movement body is called the change in its position in space relative to other bodies over time. In this case, the bodies interact according to the laws of mechanics.

The section of mechanics that describes the geometric properties of motion without taking into account the causes that cause it is called kinematics.

In more general meaning movement is called the change in the state of a physical system over time. For example, we can talk about the motion of a wave in a medium.

Types of mechanical movement

Mechanical motion can be considered for different mechanical objects:

• Movement of a material point is completely determined by the change in its coordinates in time (for example, two on a plane). The study of this is the kinematics of the point. In particular, important characteristics of motion are the trajectory of a material point, displacement, speed and acceleration.
  • rectilinear the movement of a point (when it is always on a straight line, the speed is parallel to that straight line)
  • Curvilinear motion�- movement of a point along a trajectory that is not a straight line, with arbitrary acceleration and arbitrary speed at any time (for example, movement in a circle).
• Rigid body motion consists of the movement of any of its points (for example, the center of mass) and rotational movement around this point. Studied by the kinematics of a rigid body.
  • If there is no rotation, then the movement is called progressive and is completely determined by the movement of the selected point. The movement is not necessarily linear.
  • For description rotary motion�- movements of the body relative to the selected point, for example, fixed at a point,�- use Euler angles. Their number in the case of three-dimensional space is three.
  • Also, for a solid body, flat motion�- movement, in which the trajectories of all points lie in parallel planes, while it is completely determined by one of the sections of the body, and the section of the body �- by the position of any two points.
• Continuum motion. It is assumed here that the motion of individual particles of the medium is quite independent of each other (usually limited only by the conditions of continuity of the velocity fields), so the number of defining coordinates is infinite (functions become unknown).

Motion geometry

Relativity of motion

Relativity - the dependence of the mechanical motion of the body on the frame of reference. Without specifying the reference system, it makes no sense to talk about motion.

The concept of mechanics. Mechanics is a part of physics in which they study the movement of bodies, the interaction of bodies, or the movement of bodies under some kind of interaction.

The main task of mechanics is the determination of the location of the body at any given time.

Sections of mechanics: kinematics and dynamics. Kinematics is a branch of mechanics that studies the geometric properties of motions without taking into account their masses and the forces acting on them. Dynamics is a branch of mechanics that studies the motion of bodies under the action of forces applied to them.

Motion. Movement characteristics. Motion is a change in the position of a body in space over time relative to other bodies. Characteristics of movement: distance traveled, movement, speed, acceleration.

mechanical movement – this is a change in the position of a body (or its parts) in space relative to other bodies over time.

translational movement

Uniform body movement. Demonstrated by video demonstration with explanations.

Uneven mechanical movement A motion in which a body makes unequal displacements in equal intervals of time.

Relativity of mechanical motion. Demonstrated by video demonstration with explanations.

Reference point and frame of reference in mechanical motion. The body relative to which the movement is considered is called the reference point. The reference system in mechanical movement is the reference point and the coordinate system and the clock.

Reference system. Characteristics of mechanical movement. The reference system is demonstrated by a video demonstration with explanations. Mechanical movement has characteristics: Trajectory; Path; Speed; Time.

Rectilinear trajectory is the line along which the body moves.

Curvilinear motion. Demonstrated by video demonstration with explanations.

Path and the concept of a scalar quantity. Demonstrated by video demonstration with explanations.

Physical formulas and units of measurement of mechanical motion characteristics:

Value designation	Quantity units	Formula for determining the value
Path-s	m, km	S= vt
Time- t	s, hour	T = s/v
Speed ​​-v	m/s, km/h	V = s/ t

P concept of acceleration. Revealed by a video demonstration, with explanations.

Formula for determining the amount of acceleration:

3. Newton's laws of dynamics.

Great physicist I. Newton. I. Newton debunked the ancient ideas that the laws of motion of the earth and celestial bodies completely different. The entire universe is subject to uniform laws that allow mathematical formulation.

Two fundamental problems solved by the physics of I. Newton:

1. Creation of an axiomatic basis for mechanics, which transferred this science to the category of rigorous mathematical theories.

2. Creation of dynamics linking the behavior of the body with the characteristics of external influences on it (forces).

1. Every body continues to be held in a state of rest, or uniform and rectilinear motion, until and insofar as it is forced by applied forces to change this state.

2. The change in momentum is proportional to the applied force and occurs in the direction of the straight line along which this force acts.

3. An action always has an equal and opposite reaction, otherwise, the interactions of two bodies against each other are equal and directed in opposite directions.

I. Newton's first law of dynamics. Every body continues to be held in a state of rest, or uniform and rectilinear motion, until and insofar as it is compelled by applied forces to change this state.

The concepts of inertia and inertia of a body. Inertia is a phenomenon in which the body seeks to maintain its original state. Inertia is the property of a body to maintain a state of motion. The property of inertia is characterized by the mass of the body.

Newton's development of Galileo's theory of mechanics. For a long time it was believed that in order to maintain any movement, it is necessary to carry out an uncompensated external influence from other bodies. Newton shattered these Galileo beliefs.

Inertial frame of reference. Frames of reference, relative to which a free body moves uniformly and rectilinearly, are called inertial.

Newton's first law - the law of inertial systems. Newton's first law is a postulate about the existence of inertial frames of reference. In inertial frames of reference, mechanical phenomena are described most simply.

I. Newton's second law of dynamics. In an inertial frame of reference, rectilinear and uniform motion can occur only if no other forces act on the body or their action is compensated, i.e. balanced. Demonstrated by video demonstration with explanations.

The principle of superposition of forces. Demonstrated by video demonstration with explanations.

The concept of body weight. Mass is one of the most fundamental physical quantities. Mass characterizes several properties of the body at once and has a number of important properties.

Force is the central concept of Newton's second law. Newton's second law specifies that a body will then move with acceleration when a force acts on it. Force is a measure of the interaction of two (or more) bodies.

Two conclusions of classical mechanics from the second law of I. Newton:

1. The acceleration of the body is directly related to the force applied to the body.

2. The acceleration of a body is directly related to its mass.

Demonstration of the direct dependence of the acceleration of a body on its mass

The third law of dynamics of I. Newton. Demonstrated by video demonstration with explanations.

Significance of the laws of classical mechanics for modern physics. Mechanics based on Newton's laws is called classical mechanics. Within the framework of classical mechanics, the motion of not very small bodies with not very high velocities is well described.

Demos:

Physical fields around elementary particles.

Planetary model of the atom by Rutherford and Bohr.

Movement as a physical phenomenon.

Progressive movement.

Uniform rectilinear motion

Uneven relative mechanical movement.

Video animation of reference system.

curvilinear movement.

Path and trajectory.

Acceleration.

Inertia of rest.

The principle of superposition.

Newton's 2nd law.

Dynamometer.

Direct dependence of the acceleration of a body on its mass.

Newton's 3rd law.

Control questions:.

Formulate a definition and scientific subject physics.

Formulate the physical properties common to all natural phenomena.

Formulate the main stages in the evolution of the physical picture of the world.

Name 2 main principles of modern science.

Name the features of the mechanistic model of the world.

What is the essence of molecular kinetic theory.

Formulate the main features of the electromagnetic picture of the world.

Explain the concept of a physical field.

Determine the signs and differences between electric and magnetic fields.

Explain the concepts of electromagnetic and gravitational fields.

Explain the concept of "Planetary model of the atom"

Formulate the features of the modern physical picture of the world.

Formulate the main provisions of the modern physical picture of the world.

Explain the meaning of A. Einstein's theory of relativity.

Explain the concept: "Mechanics".

Name the main sections of mechanics and give them definitions.

What are the main physical characteristics of movement.

Formulate the signs of translational mechanical motion.

Formulate signs of uniform and non-uniform mechanical motion.

Formulate signs of relativity of mechanical motion.

Explain the meaning of physical concepts: "Reference point and reference system in mechanical motion."

What are the main characteristics of mechanical motion in the frame of reference.

What are the main characteristics of the trajectory of rectilinear motion.

What are the main characteristics of curvilinear motion.

Define the physical concept: "Way".

Define the physical concept: "Scalar quantity".

Reproduce the physical formulas and units of measurement of the characteristics of mechanical movement.

Formulate the physical meaning of the concept: "Acceleration".

Reproduce the physical formula for determining the amount of acceleration.

Name two fundamental problems solved by the physics of I. Newton.

Reproduce the main meanings and content of I. Newton's first law of dynamics.

Formulate the physical meaning of the concepts of inertia and inertia of a body.

What was the development of Galileo's theory of mechanics by Newton.

Formulate the physical meaning of the concept: "Inertial frame of reference".

Why Newton's first law is the law of inertial systems.

Reproduce the main meanings and content of I. Newton's second law of dynamics.

Formulate the physical meanings of the principle of superposition of forces, derived by I. Newton.

Formulate the physical meaning of the concept of body mass.

Explain that force is the central concept of Newton's second law.

Formulate two conclusions of classical mechanics based on the second law of I. Newton.

Reproduce the main meanings and content of I. Newton's third law of dynamics.

Explain the significance of the laws of classical mechanics for modern physics.

Literature:

1. Akhmedova T.I., Mosyagina O.V. Natural Science: Tutorial/ T.I. Akhmedova, O.V. Mosyagin. - M.: RAP, 2012. - S. 34-37.

What is a reference point? What is mechanical movement?

andreus-dad-ndrey

The mechanical motion of a body is the change in its position in space relative to other bodies over time. In this case, the bodies interact according to the laws of mechanics. The section of mechanics that describes the geometric properties of motion without taking into account the causes that cause it is called kinematics.

More generally, motion is any spatial or temporal change in the state of a physical system. For example, we can talk about the motion of a wave in a medium.

* The movement of a material point is completely determined by the change in its coordinates in time (for example, two on a plane). The study of this is the kinematics of the point.
o Rectilinear movement of a point (when it is always on a straight line, the speed is parallel to this straight line)
o Curvilinear motion is the movement of a point along a trajectory that is not a straight line, with arbitrary acceleration and arbitrary speed at any time (for example, movement in a circle).
* The motion of a rigid body consists of the motion of any of its points (for example, the center of mass) and rotational motion around this point. Studied by the kinematics of a rigid body.
o If there is no rotation, then the movement is called translational and is completely determined by the movement of the selected point. Note that this is not necessarily a straight line.
o To describe the rotational movement - the movement of a body relative to a selected point, for example, fixed at a point, use Euler angles. Their number in the case of three-dimensional space is three.
o Also, for a rigid body, a plane movement is distinguished - a movement in which the trajectories of all points lie in parallel planes, while it is completely determined by one of the sections of the body, and the section of the body by the position of any two points.
* Movement of a continuum. It is assumed here that the motion of individual particles of the medium is quite independent of each other (usually limited only by the conditions of continuity of the velocity fields), so the number of defining coordinates is infinite (functions become unknown).
Relativity - the dependence of the mechanical motion of the body on the frame of reference, without specifying the frame of reference - it makes no sense to talk about motion.

Daniel Yuriev

Types of mechanical movement [edit | edit wiki text]
Mechanical motion can be considered for different mechanical objects:
The movement of a material point is completely determined by the change in its coordinates in time (for example, for a plane - by changing the abscissa and ordinate). The study of this is the kinematics of the point. In particular, important characteristics of motion are the trajectory of a material point, displacement, speed and acceleration.
Rectilinear motion of a point (when it is always on a straight line, the speed is parallel to this straight line)
Curvilinear motion - the movement of a point along a trajectory that is not a straight line, with arbitrary acceleration and arbitrary speed at any time (for example, movement in a circle).
The motion of a rigid body consists of the motion of any of its points (for example, the center of mass) and rotational motion around this point. Studied by the kinematics of a rigid body.
If there is no rotation, then the movement is called translational and is completely determined by the movement of the selected point. The movement is not necessarily linear.
To describe the rotational movement - the movement of a body relative to a selected point, for example, fixed at a point - Euler angles are used. Their number in the case of three-dimensional space is three.
Also, for a rigid body, a plane movement is distinguished - a movement in which the trajectories of all points lie in parallel planes, while it is completely determined by one of the sections of the body, and the section of the body is determined by the position of any two points.
Continuum motion. It is assumed here that the motion of individual particles of the medium is quite independent of each other (usually limited only by the conditions of continuity of the velocity fields), so the number of defining coordinates is infinite (functions become unknown).

mechanical movement. Path. Speed. Acceleration

Lara

Mechanical movement is a change in the position of a body (or its parts) relative to other bodies.
The position of the body is given by a coordinate.
The line along which the material point moves is called the trajectory. The length of the trajectory is called the path. The unit of the path is the meter.
Path = speed * time. S=v*t.

Mechanical motion is characterized by three physical quantities: displacement, speed and acceleration.

A directed line segment drawn from the initial position of the moving point to its final position is called displacement (s). Displacement is a vector quantity. The unit of movement is the meter.

Speed ​​is a vector physical quantity that characterizes the speed of movement of a body, numerically equal to the ratio of movement in a small period of time to the value of this period of time.
The speed formula is v = s/t. The unit of speed is m/s. In practice, the speed unit used is km/h (36 km/h = 10 m/s).

Acceleration is a vector physical quantity that characterizes the rate of change in speed, numerically equal to the ratio of the change in speed to the period of time during which this change occurred. Formula for calculating acceleration: a=(v-v0)/t; The unit of acceleration is meter/(square second).

Mechanical movement body (point) is called a change in its position in space relative to other bodies over time.

Types of movements:

A) Uniform rectilinear motion of a material point: Initial conditions

. Initial conditions

G) Harmonic oscillatory motion. An important case of mechanical motion is oscillations, in which the parameters of the motion of a point (coordinates, velocity, acceleration) are repeated at certain intervals of time.

O motion scriptures . There are various ways to describe the motion of bodies. With the coordinate method setting the position of the body in the Cartesian coordinate system, the movement of a material point is determined by three functions that express the dependence of coordinates on time:

x= x(t), y=y(t) and z= z(t) .

This dependence of coordinates on time is called the law of motion (or the equation of motion).

With the vector method the position of a point in space is determined at any time by the radius vector r= r(t) , drawn from the origin to the point.

There is another way to determine the position of a material point in space for a given trajectory of its movement: using a curvilinear coordinate l(t) .

All three ways of describing the motion of a material point are equivalent, the choice of any of them is determined by considerations of the simplicity of the resulting equations of motion and the clarity of the description.

Under reference system understand the body of reference, which is conditionally considered to be motionless, the coordinate system associated with the body of reference, and the clock, also associated with the body of reference. In kinematics, the frame of reference is chosen in accordance with the specific conditions of the problem of describing the motion of a body.

2. Trajectory of movement. Distance traveled. Kinematic law of motion.

The line along which a certain point of the body moves is called trajectorymovements this point.

The length of the section of the trajectory traversed by the point during its movement is called the way we have traveled .

The change in the radius vector over time is called kinematic law :
In this case, the coordinates of the points will be the coordinates in time: x= x(t), y= y(t) andz= z(t).

With curvilinear motion, the path is greater than the displacement modulus, since the length of the arc is always greater than the length of the chord that tightens it

The vector drawn from the initial position of the moving point to its position at a given moment of time (the increment of the radius vector of the point over the considered time interval) is called moving. The resulting displacement is equal to the vector sum of successive displacements.

With rectilinear motion, the displacement vector coincides with the corresponding section of the trajectory, and the displacement modulus is equal to the distance traveled.

3. Speed. Average speed. Velocity projections.

Speed - the speed of change of coordinates. When a body (material point) moves, we are interested not only in its position in the chosen frame of reference, but also in the law of motion, i.e., the dependence of the radius vector on time. Let the moment of time corresponds to the radius vector moving point, but to a close point in time - radius vector . Then in a short period of time
the point will make a small displacement equal to

To characterize the motion of a body, the concept is introduced average speed his movements:
This quantity is vector, coinciding in direction with the vector
. With an unlimited reduction Δt the average speed tends to the limit value, which is called the instantaneous speed :

Velocity projections.

A) Uniform rectilinear motion of a material point:
Initial conditions

B) Uniformly accelerated rectilinear motion of a material point:
. Initial conditions

C) The movement of the body along the arc of a circle with a constant modulo speed:

In physics, there is such a thing as mechanical motion, the definition of which is interpreted as a change in the coordinates of a body in three-dimensional space relative to other bodies with the expenditure of time. Oddly enough, but without moving anywhere you can exceed, for example, the speed of a bus. This value is relative and dependent on a given point. The main thing is to fix the reference system in order to observe the point in relation to the object.

In contact with

Description

Concepts from physics:

1. A material point is a part of the body or an object with small parameters and mass, which are not taken into account when studying the process. This is a quantity that is neglected in physics.
2. Displacement is the distance traveled by a material point from one coordinate to another. The concept should not be confused with movement, since in physics it is the definition of a path.
3. The path traveled is the area that the item has traveled. What is the distance traveled considers the section of physics under titled "Kinematics".
4. A trajectory in space is a straight or broken line along which an object travels a path. To imagine what a trajectory is, according to the definition from the field of physics, you can mentally draw a line.
5. Mechanical movement is called movement along a given trajectory.

Attention! The interaction of bodies is carried out according to the laws of mechanics, and this section is called kinematics.

Understand what a coordinate system is, and what is a trajectory in practice?

It is enough to mentally find a point in space and draw coordinate axes from it, an object will move relative to it along a broken or straight line, and the types of movement will also be different, including translational, carried out during vibration and rotation.

For example, a cat is in a room, moves to any object, or changes its location in space, moving along different trajectories.

The distance between objects may differ because the selected paths are not the same.

Types

Known types of movement:

1. Translational. It is characterized by the parallelism of two interconnected points moving in the same way in space. An object moves forward when it passes along a single line. It suffices to imagine the replacement of the rod in ballpoint pen, that is, the rod moves forward along a given path, while each part of it moves in parallel and equally. Quite often this occurs in the mechanisms.
2. Rotational. The object describes a circle in all planes that are parallel to each other. The axes of rotation are the centers of the described, and the points located on the axis are fixed. The rotating axis itself can be located inside the body (rotational), and also connected to its outer points (orbital). To understand what it is, you can take a regular needle and thread. Pinch the latter between your fingers and gradually unwind the needle. The needle will describe a circle, and such types of movement should be referred to as orbital. An example of a rotational view: spinning an object on a hard surface.
3. vibrational. All points of a body moving along a given trajectory are repeated exactly or approximately after the same time. illustrative example- a washer suspended on a cord, oscillating to the right and to the left.

Attention! Progressive motion feature. An object moves in a straight line, and in any time interval all its points move in the same direction - this is translational motion. If a bicycle rides, then at any time you can separately consider the trajectory of its any point, it will be the same. At the same time, it doesn't matter Smooth surface or not.

These types of movements are encountered daily in practice, so losing them mentally is not difficult.

What is relativity

According to the laws of mechanics, an object moves relative to a point.

For example, if a person is standing still, and the bus is moving, this is called the relativity of the movement of the considered vehicle to the object.

With what speed the object moves in relation to a certain body in space is also taken into account relative to this body and, accordingly, acceleration also has a relative characteristic.

Relativity is a direct dependence of the trajectory given during the movement of the body, the path traveled, the speed characteristic, and also the displacement with respect to reference systems.

How is the countdown

What is a reference system and how is it characterized? The reference in connection with the spatial coordinate system, the primary reference of the time of movement - this is the reference system. V different systems one body can have a different location.

The point is in the coordinate system, when it starts to move, its movement time is taken into account.

Reference body - this is an abstract object located at a given point in space. When orienting to its position, the coordinates of other bodies are considered. For example, a car is standing still, and a person is moving, in this case, the body of reference is a car.

Uniform movement

The concept of uniform motion - this definition in physics is interpreted as follows.