1. Smooth (friction-free) plane or surface. Such connections prevent the body from moving only in the direction of the common normal at the point of contact, along which the corresponding reaction will be directed. Therefore, the reaction of a smooth flat support is perpendicular to this support (reaction in Fig. 12,a); the reaction of a smooth wall is perpendicular to this wall Fig. 12, b); the reaction of a smooth surface is directed along the normal to this surface, drawn at the point of contact in Fig. 12, c).
2. Sharp protrusion. In this case, we can assume that the protrusion itself is supported, and the body in question serves as a support. This leads to case 1 and the conclusion that the reaction of a smooth protrusion is directed normal to the surface of the supporting body (force in Fig. 12, c).
3. Flexible connection (weightless thread, cable, chain, etc.). The corresponding reaction is directed along the connection from the point of attachment of the thread to the point of suspension (force in Fig. 11, d, force in Fig. 12, b).
4. Weightless straight rod with hinges at the ends. The reaction is directed along the rod. Since the rod can be either compressed or stretched, the reaction can be directed both towards the suspension point of the rod and away from the suspension point (reactions in Fig. 13, a).
5. Weightless cranked or curved rod. The reaction is directed along a straight line passing through the centers of the end hinges (force 53 in Fig. 13, a; force S in Fig. 13, b).
6. Movable hinge support. The reaction is directed perpendicular to the support plane (rolling plane) (Fig. 14, a, b).
7. Cylindrical hinge (Fig. 15, a), radial bearing (Fig. 15, b). The reaction passes through the center of the hinge (the center of the middle section of the bearing) and lies in a plane perpendicular to the axis of the hinge (bearing).
It is equivalent to two forces unknown in magnitude - the components of this reaction along the corresponding coordinate axes (forces in Fig. 15, a; and in Fig. 15, b). (For an explanation of this, see also the example on page 16).
8. Spherical hinge (Fig. 16, a), thrust bearing (or angular contact bearing) (Fig. 16, b). The reaction consists of three forces unknown in magnitude - the components of the reaction along the axes of the spatial coordinate system.
9. Hard seal (Fig. 17). When a plane system of forces acts on a body, the total reaction of the embedment consists of a force with components XA and UA, and a pair of forces with a moment M, located in the same plane as the acting forces.
10. Sliding seal (Fig. 18). In the case of a plane system of forces and the absence of friction, the reaction consists of a force N and a pair of forces with a moment M, located in the same plane as the acting forces. The force N is perpendicular to the direction of sliding.
Self-test questions
1. What is called an absolutely rigid body, a material point?
2. Identify the elements of force. In what ways can you set the force?
3. What is called the vector moment of force relative to a point? What is the algebraic moment of force?
4. In what case is the moment of a force relative to a point equal to zero?
5. What is called a system of forces? What systems of forces are called equivalent?
6. What is called the resultant system of forces?
7. Define a non-free solid, bond, bond reaction?
8. Can a non-free body be considered as free?
9. What two groups are forces acting on a non-free rigid body divided into?
Lecture 1
INTRODUCTION BASIC CONCEPTS OF STATICS
Mechanics subject.
Basic concepts and axioms of statics.
Connections and reactions of connections.
Mechanics subject
Mechanics is a science that studies the basic laws of mechanical motion, i.e. laws of changes in the relative position of material bodies or particles in a continuous medium over time. The content of a course in theoretical mechanics at a technical university is the study of the equilibrium and motion of absolutely rigid bodies, material points and their systems. Theoretical mechanics is the basis for many general professional disciplines (strength of materials, machine parts, theory of machines and mechanisms, etc.), and also has independent ideological and methodological significance. Illustrates the scientific method of understanding the laws of the world around us - from observation to a mathematical model, its analysis, obtaining solutions and their application in practical activities.
The theoretical mechanics course is traditionally divided into three parts:
Statics studies the rules of equivalent transformation and equilibrium conditions for systems of forces.
Kinematics considers the movement of bodies from the geometric side, without taking into account the forces causing this movement.
Dynamics studies the movement of bodies in connection with the forces acting on them.
Main tasks of statics:
Study of methods for converting one force system into another that is equivalent to data.
Establishing conditions for equilibrium of systems of forces.
Basic concepts and axioms of statics
Force a measure of the mechanical effect of one body on another. The physical nature of forces is not considered in mechanics.
The force is specified by the module, direction and point of application. Indicated in capital letters of the Latin alphabet: 
force modulus. Analy-
Technically, the force can be specified by its projections on the coordinate axes: 
,
,
, and the direction in space is the direction cosines: 
,
,
.
The combination of several forces acting on a rigid body is called system of forces. Two systems of forces equivalent() among themselves, if, without disturbing the state of the body, one system of forces can be replaced by another.
The force equivalent to a given system of forces is called resultant:
. It is not always possible to replace a system of forces with a resultant one.
A system of forces applied to a free rigid body in equilibrium and not removing it from this state is called balanced system of forces
~
0.
Absolutely rigid body a body in which the distance between any two points remains unchanged.
Axioms:
Consequence: The point of application of the force can be moved along the line of action of the force.
Proof:
To the body at a point A force applied 
. Add at point IN system of forces 
:
.
, But 
, hence, 
. The investigation has been proven.
Two forces applied to a body at one point have a resultant force passing through this point and equal to their geometric sum.
,
,
From this axiom it follows that a force can be decomposed into any number of force components along pre-selected directions.
The forces of interaction between two bodies are equal in magnitude and directed along one straight line in opposite directions.
The equilibrium of a deformable body will not be disturbed if this body hardens.
In other words, the necessary equilibrium conditions for deformable and absolutely rigid bodies coincide, which makes it possible to apply the results obtained to real bodies and structures that are not absolutely rigid.
Connections and reactions of connections
The body is called free, if its movement in space is not limited by anything. Otherwise the body is called unfree, and the bodies limiting the movement of a given body are connections. The forces with which bonds act on a given body are called reactions of connections.
Main types of connections and their reactions:
The reaction of a smooth surface is directed normal to this surface (perpendicular to the common tangent).
The reaction is perpendicular to the supporting surface.
Perfect thread(flexible, weightless, inextensible):
Examples: models a cable, rope, chain, belt,...
The reaction of an ideal thread is directed along the thread to the suspension point.
Ideal rod(a rigid, weightless rod with hinges at the ends):
The coupling reaction is directed along the rod.
Unlike a thread, a rod can also work under compression.
Cylindrical joint:
This connection allows the body to move along the axis and rotate around the hinge axis, but does not allow the attachment point to move in a plane perpendicular to the hinge axis. The reaction lies in a plane perpendicular to the hinge axis and passes through it. The position of this reaction is not determined, but it can be represented by two mutually perpendicular components.
Spherical joint:
This connection prevents the body’s anchor point from moving in any direction. The position of the reaction is not defined, but it can be represented by three mutually perpendicular components.
Thrust bearing:
The reaction of this connection is set similarly to the previous case.
Hard termination:
This connection prevents movement and rotation around the anchor point. Contact of the body with the connection is carried out along the surface. We have a distributed system of reaction forces, which, as will be shown, can be replaced by one force and a pair of forces.
Axiomrelease from ties:
Literature: [ 1 , §13];
[2 , §13];
[ 3 , clause 1.11.4].
Any free body in space has six degrees of freedom: it can move along three axes and rotate about these axes. Bodies are rarely in a free state; in most cases, their movement is limited by connections. Constraints are restrictions that exclude the possibility of a body moving in a certain direction. If active forces act on a fixed body, then reactive forces or reactions arise in the connections, complementing the system of active forces to an equilibrium one. The combination of active and reactive balanced forces determines the stressed state of the body and its deformation.
Bond reactions are found using equilibrium equations. In this case, the decision is carried out according to the following plan:
- identify external active forces applied to a selected body or group of bodies;
- the selected object (body) is freed from the bonds and reaction forces of the bonds are applied instead;
- Having chosen the coordinate axes, they compose equilibrium equations and, having solved them, find the reaction forces of the bonds.
For a spatial system of forces, six equilibrium equations (13.7) can be compiled. Using these equations, six unknown reactions are determined.
Problems that can be solved only using static equilibrium equations are called statically definable. If a larger number of connections are imposed on the selected object, then the task becomes statically indeterminate and to solve it, in addition to the equilibrium equations, it is necessary to use additional equations compiled on the basis of deformation analysis. In general, securing or connecting two parts can eliminate from one to six degrees of freedom, i.e. impose from one to six connections. In accordance with this, from one to six reactions can occur in consolidation. The amount of reactive forces and their direction depend on the nature of the connections.
Here are the most common types of fastening and connecting parts.
- 1. Connections that exclude the possibility of movement in only one direction. In such compounds, only one reaction of a certain direction occurs. Connections of this type include:
- a) connection by touching two bodies at a point or along a line. When touched, a reaction occurs directed along the general normal to the touching surfaces (Fig. 13.5). Such a connection is called articulated-movable;
Rice. 13.5.
- b) the connection made by a cable, thread, chain gives a reaction directed along a flexible connection, and such a connection can only work in tension (see Fig. 13.5, b);
- c) a connection in the form of a rigid straight rod with hinged ends also gives a reaction directed along the axis of the rod (see Fig. 13.5, c) at but can work in both tension and compression.
Rice. 13.6.
In Fig. 13.5, G a body is shown with three constraints imposed on it; each connection excludes the possibility of movement in one direction and gives one reaction, the direction of which is known.
- 2. A fastening or connection that excludes movement in two directions and, accordingly, gives two reactions, is called a hinged-fixed support or a cylindrical hinge (Fig. 13.6).
- 3. A connection that excludes movement in three directions and gives three reactions is called a spatial or ball joint (Fig. 13.7).
- 4. Fastening that excludes all six degrees of freedom is called rigid fastening or embedding. Six reactive force factors can arise in the embedding - three reactive forces and three reactive moments (Fig. 13.8). When forces located in one plane act on a body with a rigid embedding, two reactive forces and one reactive moment arise in the embedding.
Rice. 13.7.
Rice. 13.8.
When making calculations, supports are schematized and conditionally divided into three main groups:
- articulated and movable(Fig. 13.9, A), perceiving only one linear reaction /?;
- articulated-fixed(Fig. 13.9, b), perceiving two linear reactions R And N.
- pinching, or sealing(Fig. 13.9, V), perceiving linear reactions R And N and moment M.
Rice. 13.9.
When real bodies come into contact and during their relative motion, friction forces arise at the places of their contact, which can be considered as a special type of reactive forces. The friction force is located in the plane of contact of the bodies; when moving, it is directed in the direction opposite to the relative speed of the body.
Example. Shaft 1 with gear 2 attached to it is mounted in two bearings A And IN. A belt drive pulley 3 is mounted on the free end of the shaft (Fig. 13.10). The geometric dimensions are known. A, s, transmitting torque M, pulley diameter D, all parameters of the bevel gear, as well as the ratio of belt tension forces F a JF al= 2. It is necessary to determine the reaction of the supports and the tension force of the belt.
Rice. 13.10.
We carry out the solution in three steps.
1. We identify the active forces acting in the system. A spatially located force acts on a bevel gear, the components of which along the coordinate axes are designated accordingly F v F r And F a . Component F ( , called circumferential force, is determined by a given torque based on the equation of moments about the axis z
Radial component F r and axial component F a determined by circumferential force F ( based on the specified geometry of the bevel gear.
2. We free the shaft (equilibrium object) from the connections and instead apply reaction forces X l U l, X c, Y B Z B .
Bearings A And IN should be considered as hinged supports, since they always have gaps. In support A two reactions occur X l And U l, since this support prohibits the movement of the shaft only in transverse directions. Three reactions occur in the right support X in, U in And Z B , since it limits the movement of the shaft also in the axial direction. Active and reactive forces together form a spatial system of balanced forces.
3. Select a coordinate system: axes X And at placed in a plane perpendicular to the axis of the shaft, and the axis z we direct along the axis of the shaft. We create six equilibrium equations using (13.7) and (13.8).
Using a given condition F al = 2F ii2 and solving the equilibrium equations, we find the forces F aV F a2 and support reactions
This publication will help you systematize previously acquired knowledge, as well as prepare for an exam or test and pass it successfully.
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by liters company.
2. Connections and reactions of connections
All bodies are divided into free and bound.
Free bodies– these are bodies whose movement is not limited.
Bound bodies- these are bodies whose movement is limited by other bodies.
Bodies that limit the movement of other bodies are called connections.
The forces acting from connections and preventing movement are called reactions of connections. The communication reaction is always directed from the side where it cannot be moved.
Any bound body can be imagined as free if the bonds are replaced by reactions (the principle of liberation from bonds).
Connections are divided into several types.
Connection – smooth support(without friction) - the support reaction is applied at the support point and is always directed perpendicular to the support.
Flexible communication(thread, rope, cable, chain) – the load is suspended on two threads. The reaction of the thread is directed along the thread away from the body, and the thread can only be stretched.
Hard rod– the rod can be compressed or stretched. The reaction of the rod is directed along the rod. The rod works in tension or compression. The exact direction of the reaction is determined by mentally removing the rod and considering possible movements of the body without this connection.
Possible relocation point is called such an infinitesimal mental movement that is allowed at a given moment.
Articulated support. The hinge allows rotation around the attachment point. There are two types of hinges.
Movable hinge. The rod attached to the hinge can rotate around the hinge, and the attachment point can move along the guide (platform). The reaction of the movable hinge is directed perpendicular to the supporting surface, since only movement across the supporting surface is not allowed.
Fixed hinge. The attachment point cannot be moved.
The rod can rotate freely around the hinge axis. The reaction of such a support passes through the hinge axis, but its direction is unknown. It is depicted as two components: horizontal and vertical ( R x , R y).
Pinching, or "sealing". Any movement of the attachment point is not possible.
Under the influence of external forces, a reactive force and a reactive moment arise in the support M z, preventing rotation.
The reactive force is represented as two components along the coordinate axes:
R = R x + R y .
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The given introductory fragment of the book Technical mechanics. Crib (Aurika Lukovkina, 2009) provided by our book partner -
In the process of studying statics, which is one of the constituent branches of mechanics, the main role is given to axioms and basic concepts. There are only five basic axioms. Some of them are known from school physics lessons, since they are Newton's laws.
Definition of mechanics
To begin with, it is necessary to mention that statics is a subsection of mechanics. The latter should be described in more detail, since it is directly related to statics. At the same time, mechanics is a more general term that combines dynamics, kinematics and statics. All these subjects were studied in the school physics course and are known to everyone. Even the axioms included in the study of statics are based on those known from school years. However, there were three of them, while the basic axioms of statics were five. Most of them concern the rules for maintaining balance and rectilinear uniform movement of a certain body or material point.
Mechanics is the science of the simplest method of motion of matter - mechanical. The simplest movements are considered to be actions that can be reduced to moving a physical object in space and time from one position to another.
What does mechanics study?
In theoretical mechanics, the general laws of motion are studied without taking into account the individual properties of the body, except for the properties of extension and gravity (from this follow the properties of matter particles to attract each other or have a certain weight).
Basic definitions include mechanical force. This term refers to movement that is mechanically transmitted from one body to another during interaction. Based on numerous observations, it was determined that force is considered to be characterized by the direction and point of application.
According to the method of construction, theoretical mechanics is similar to geometry: it is also based on definitions, axioms and theorems. However, the connection does not end with simple definitions. Most of the drawings related to mechanics in general and statics in particular contain geometric rules and laws.
Theoretical mechanics includes three subsections: statics, kinematics and dynamics. The first studies methods for transforming forces applied to an object and an absolutely rigid body, as well as the conditions for the emergence of equilibrium. Kinematics considers simple mechanical motion that does not take into account the acting forces. In dynamics, the movements of a point, a system, or a rigid body are studied, taking into account the acting forces.
Axioms of statics
To begin with, we should consider the basic concepts, axioms of statics, types of connections and their reactions. Statics is a state of equilibrium with forces that are applied to an absolutely rigid body. Its tasks include two main points: 1 - the basic concepts and axioms of statics include the replacement of an additional system of forces that were applied to the body by another system equivalent to it. 2 - derivation of general rules under which a body, under the influence of applied forces, remains in a state at rest or in the process of uniform translational rectilinear motion.
Objects in such systems are usually called a material point - a body, the dimensions of which can be omitted under the given conditions. A set of points or bodies interconnected in some way is called a system. The forces of mutual influence between these bodies are called internal, and the forces influencing this system are called external.
The resultant force in a certain system is a force equivalent to the reduced system of forces. Those included in this system are called component forces. The balancing force is equal in magnitude to the resultant force, but is directed in the opposite direction.
In statics, when deciding on a change in the system of forces affecting a solid body, or on the balance of forces, the geometric properties of force vectors are used. From this the definition of geometric statics becomes clear. Analytical statics, based on the principle of permissible displacements, will be described in dynamics.
Basic concepts and axioms of statics
The conditions for a body to be in equilibrium are derived from several basic laws that are used without additional evidence, but have confirmation in the form of experiments, called axioms of statics.
- Axiom I is called Newton's first law (axiom of inertia). Each body remains in a state of rest or uniform linear motion until external forces act on this body, removing it from this state. This ability of the body is called inertia. This is one of the basic properties of matter.
- Axiom II - Newton's third law (axiom of interaction). When one body acts on another with a certain force, then the second body, together with the first, will act on it with a certain force, which is equal in magnitude and opposite in direction.
- Axiom III is the condition for the equilibrium of two forces. To obtain equilibrium of a free body that is under the influence of two forces, it is enough that these forces are identical in magnitude and opposite in direction. This is also related to the next point and is included in the basic concepts and axioms of statics, the equilibrium of a system of converging forces.
- Axiom IV. Equilibrium will not be disturbed if a balanced system of forces is applied or removed to a solid body.
- Axiom V is the axiom of the parallelogram of forces. The resultant of two intersecting forces is applied at the point of their intersection and is represented by the diagonal of a parallelogram constructed on these forces.
Connections and their reactions
In theoretical mechanics, a material point, system and solid body can be given two definitions: free and non-free. The differences between these words are that if pre-specified restrictions are not imposed on the movement of a point, body or system, then these objects will be, by definition, free. In the opposite situation, objects are usually called non-free.
Physical circumstances leading to restriction of the freedom of these material objects are called connections. In statics there may be the simplest connections performed by various rigid or flexible bodies. The force of a connection on a point, system or body is called the reaction of the connection.
Types of connections and their reactions
In ordinary life, connection can be represented by threads, laces, chains or ropes. In mechanics, this definition is taken to be weightless, flexible and inextensible bonds. Reactions can accordingly be directed along a thread or rope. In this case, connections take place, the lines of action of which cannot be determined immediately. As an example of the basic concepts and axioms of statics, we can cite a fixed cylindrical hinge.
It consists of a stationary cylindrical bolt, onto which is mounted a sleeve with a cylindrical hole, the diameter of which does not exceed the size of the bolt. When fastening the body to the bushing, the first can only rotate along the hinge axis. In an ideal hinge (provided that the friction between the surface of the bushing and the bolt is neglected), a barrier appears to the displacement of the bushing in a direction perpendicular to the surface of the bolt and bushing. In this regard, the reaction in an ideal hinge is directed along the normal - the radius of the bolt. Under the influence of acting forces, the bushing is capable of pressing against the bolt at an arbitrary point. In this regard, the direction of reaction at a fixed cylindrical hinge cannot be determined in advance. From this reaction, only its location in the plane perpendicular to the hinge axis can be known.
When solving problems, the reaction of the hinge will be determined analytically by decomposing the vector. The basic concepts and axioms of statics include this method. The reaction projection values are calculated from the equilibrium equations. The same is done in other situations, including the impossibility of determining the direction of the bond reaction.
System of converging forces
Basic definitions include a system of forces that converge. The so-called system of converging forces will be called a system in which the lines of action intersect at a single point. This system leads to a resultant or is in a state of equilibrium. This system is also taken into account in the previously mentioned axioms, since it is associated with maintaining the balance of the body, which is stated in several positions at once. The latter indicate both the reasons necessary to create equilibrium, and factors that will not cause a change in this state. The resultant of a given system of converging forces is equal to the vector sum of the named forces.
Equilibrium of the system
In the basic concepts and axioms of statics, the system of converging forces is also included in the study. For the system to be in equilibrium, the mechanical condition is the zero value of the resultant force. Since the vector sum of forces is zero, the polygon is considered closed.
In analytical form, the condition for equilibrium of the system will be as follows: a spatial system of converging forces that is in equilibrium will have an algebraic sum of force projections on each of the coordinate axes equal to zero. Since in such an equilibrium situation the resultant will be zero, the projections on the coordinate axes will also be zero.
Moment of power
This definition means the vector product of the vector of the point of application of forces. The vector of the moment of force is directed perpendicular to the plane in which the force and the point lie, in the direction from which the rotation from the action of the force is seen occurring counterclockwise.
Couple of forces
This definition refers to a system consisting of a pair of parallel forces, equal in magnitude, directed in opposite directions and applied to a body.
The moment of a pair of forces can be considered positive if the forces of the pair are directed counterclockwise in a right-handed coordinate system, and negative if they are directed clockwise in a left-handed coordinate system. When transferring from the right coordinate system to the left, the orientation of the forces changes to the opposite. The minimum value of the distance among the lines of action of forces is called the shoulder. It follows from this that the moment of a pair of forces is a free vector, modulo equal to M = Fh and having a direction perpendicular to the plane of action, and from the top of this vector the forces were oriented positively.
Equilibrium in arbitrary systems of forces
The required equilibrium condition for an arbitrary spatial system of forces applied to a rigid body is considered to be the vanishing of the main vector and moment with respect to any point in space.
It follows from this that in order to achieve equilibrium of parallel forces located in one plane, it is required and sufficient that the resulting sum of the projections of forces onto a parallel axis and the algebraic sum of all components of the moments provided by the forces relative to a random point is equal to zero.
Center of gravity of the body
According to the law of universal gravitation, every particle located near the surface of the Earth is affected by attractive forces called gravity. With small body sizes, in all technical applications the gravity forces of individual particles of the body can be considered a system of almost parallel forces. If we consider all the gravitational forces of particles to be parallel, then their resultant will be numerically equal to the sum of the weights of all particles, i.e., the weight of the body.
Subject of kinematics
Kinematics is a section of theoretical mechanics that studies the mechanical motion of a point, a system of points and a rigid body, regardless of the forces influencing them. Newton, based on a materialist position, considered the objective nature of space and time. Newton used the definition of absolute space and time, but separated them from moving matter, so he can be called a metaphysician. Dialectical materialism considers space and time to be objective forms of existence of matter. Space and time cannot exist without matter. In theoretical mechanics it is said that the space that includes moving bodies is called three-dimensional Euclidean space.
Compared to theoretical mechanics, the theory of relativity is based on different ideas about space and time. This was helped by the emergence of a new geometry created by Lobachevsky. Unlike Newton, Lobachevsky did not separate space and time from vision, considering the latter to be a change in the position of some bodies relative to others. In his own work, he pointed out that in nature only movement is cognized by man, without which sensory representation becomes impossible. It follows from this that all other concepts, for example, geometric ones, are created artificially by the mind.
From this it is clear that space is considered as a manifestation of the connection between moving bodies. Almost a century before the emergence of the theory of relativity, Lobachevsky pointed out that Euclidean geometry relates to geometrically abstract systems, while in the physical world spatial relationships are determined by physical geometry, which differs from Euclidean geometry, in which the properties of time and space are combined with the properties of matter moving in space and time.
It does not hurt to note that advanced scientists from Russia in the field of mechanics consciously adhered to the correct materialist positions in the interpretation of all the main definitions of theoretical mechanics, in particular time and space. At the same time, the opinion about space and time in the theory of relativity is similar to the ideas about space and time of the supporters of Marxism, which were created before the appearance of works on the theory of relativity.
When working with theoretical mechanics when measuring space, the meter is taken as the main unit, and the second is taken as time. Time is the same in each reference system and is independent of the interleaving of these systems in relation to each other. Time is indicated by a symbol and is considered as a continuous variable value used as an argument. When measuring time, the definitions of a period of time, a moment in time, and initial time are used, which are included in the basic concepts and axioms of statics.
Technical mechanics
In practical application, the basic concepts and axioms of statics and technical mechanics are interconnected. In technical mechanics, both the mechanical process of motion itself and the possibility of using it for practical purposes are studied. For example, when creating technical and building structures and testing them for strength, which requires a brief knowledge of the basic concepts and axioms of statics. However, such a brief study is suitable only for amateurs. In specialized educational institutions, this topic is of considerable importance, for example, in the case of the system of forces, basic concepts and axioms of statics.
In technical mechanics, the above axioms are also used. To 1, the basic concepts and axioms of statics are related to this section. Despite the fact that the very first axiom explains the principle of maintaining equilibrium. In technical mechanics, an important role is played not only by the creation of devices, but also in the construction of which stability and strength are the main criteria. However, it will be impossible to create something like this without knowing the basic axioms.
General remarks
The simplest forms of movement of solid bodies include translational and rotational movement of the body. In the kinematics of rigid bodies for different types of movements, the kinematic characteristics of the movement of its different points are taken into account. Rotational motion of a body around a fixed point is a motion in which a straight line passing through a pair of arbitrary points during the motion of the body remains at rest. This straight line is called the axis of rotation of the bodies.
The text above briefly summarized the basic concepts and axioms of statics. At the same time, there is a large amount of third-party information with which you can better understand statics. Do not forget the basic data; in most examples, the basic concepts and axioms of statics include an absolutely rigid body, since this is a kind of standard for an object that may not be achievable under normal conditions.
Then you should remember the axioms. For example, the basic concepts and axioms of statics, communications and their reactions are among them. Despite the fact that many axioms only explain the principle of maintaining balance or uniform motion, this does not negate their significance. Starting from the school course, these axioms and rules are studied, since they are Newton’s laws that are well known to everyone. The need to mention them is associated with the practical application of information from statics and mechanics in general. An example was technical mechanics, in which, in addition to creating mechanisms, it is necessary to understand the principle of constructing sustainable buildings. Thanks to such information, the correct construction of conventional structures is possible.
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