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T.I.Trofimova
PHYSICS COURSE
The edition the seventh, stereotypic
It is recommended the Ministry of Education
The Russian Federation as the manual for technical specialities
Higher educational institutions
Moscow
THE HIGHER SCHOOL
2003
The manual is written according to operating program of a course of physics for technical specialities of higher educational institutions and intended for students of the higher technical educational institutions of day mode of study with the limited number of hours on the physicist, with possibility of its use on evening and correspondence modes of study.
Small volume of the manual will reach by means of careful selection and a laconic statement of a material.
The book consists of seven parts. In the first part the regular statement of physical bases of classical mechanics is given, and also elements of the special (private) theory of a relativity are considered. The second part is devoted bases of molecular physics and thermodynamics. In the third part the electrostatics, a constant electric current and electromagnetism are studied. In the fourth part devoted to a statement of the theory of fluctuations and waves, mechanical and electromagnetic fluctuations are considered in parallel, their similarities and distinction are specified and the physical processes occurring at corresponding fluctuations are compared. In the fifth part elements of geometrical and electronic optics, wave optics and the quantum nature of radiation are considered. The sixth part is devoted elements of quantum physics of atoms, molecules and firm bodies. In the seventh part elements of physics of an atomic nucleus and elementary particles are stated.
The material statement is conducted without bulky mathematical calculations, the proper attention addresses on a physical essence of the phenomena and concepts describing them and laws, and also on continuity of modern and classical physics. All biographic data is resulted under "Physics" Ju.A.Hramova's book (М: the Science, 1983).
For a designation of vector sizes in all drawings and in the text the bold-face type, except for the sizes designated by the Greek letters which for technical reasons are typed in the text by a light font with an arrow is used.
The author expresses deep gratitude to colleagues and readers, whose benevolent remarks and wishes promoted book improvement. I am especially grateful to the professor Kasyanov V. A for reviewing of the grant and the remarks made it.
The author will be grateful for remarks and councils about grant improvement. The request to direct them to publishing house "Higher school" to the address: 127994, Moscow, GSP-4, street Neglinnaja, д. 29/14.
The author
Surrounding you the world, all existing round us and found out by us by means of sensations represents a matter.
The integral property of a matter and the form of its existence is movement. Movement in the broad sense of the word are every possible changes of a matter - from simple moving before the most complicated processes of thinking.
Various forms of movement of a matter are studied by various sciences, including physics. A physics subject as, however, and any science, can be opened only in process of its detailed statement. To make strict definition of a subject of physics difficult enough because borders between physics and a number of related subjects are conditional. At the given stage of development it is impossible to keep physics definition only as sciences about the nature.
Academician A.F.Ioffe (1880-1960; the Russian physicist) * has defined physics as a science studying the general properties and laws of movement of substance and a field. Now it is conventional that all interactions are carried out by means of fields, for example gravitational, electromagnetic, fields of nuclear forces. The field along with substance is one of existence forms материн. Indissoluble communication of a field and substance, and also distinction in their properties will be considered in process of course studying.
Physics - a science about the most simple and at the same time the most general forms of movement of a matter and their mutual transformations. Forms of movement of a matter studied by physics (mechanical, thermal, etc.) are present at all higher and more difficult forms of movement of a matter (chemical, biological, etc.). Therefore they, being the most simple, are at the same time most the general forms of movement of a matter. The higher and more difficult forms of movement of a matter - a subject of studying of other sciences (chemistry, biology, etc.).
The physics is closely connected with natural sciences. This теснейшая communication of physics with other branches of natural sciences as academician S.I.Vavilov (1891-1955 marked; the Russian physicist and the public figure), has led to that the physics the deepest roots has grown into astronomy, geology, chemistry, biology and other natural sciences. A number of new related subjects, such, as astrophysics, biophysics was as a result formed, etc.
The physics is closely connected and with technics, and this communication has bilateral character. The physics has grown from requirements of technics (development of mechanics in ancient Greeks, for example, it has been caused by inquiries building and military technology of that time), and the technics, in turn, defines a direction of physical researches (for example, in due time the problem of creation of the most economic thermal engines has caused thermodynamics rapid development). On the other hand, the manufacture technological level depends on physics development. Physics - base for creation of new branches of technics (the electronic technics, the nuclear technics, etc.).
Rough rate of development of physics, its growing communications with technics specify in a considerable role of a course of physics in technical college: it is fundamental base for theoretical preparation of the engineer without which its successful activity is impossible.
The basic method of research in the physicist is experience - the is sensual-empirical knowledge of the objective validity based on practice, i.e. supervision of the investigated phenomena of precisely considered conditions, allowing to watch a course of the phenomena and repeatedly to reproduce it at repetition of these conditions.
For an explanation of the experimental facts hypotheses are put forward.
The hypothesis is the scientific assumption which is put forward for an explanation of any phenomenon and demanding check on experience and a theoretical substantiation to become the authentic scientific theory.
As a result of generalisation of the experimental facts, and also results of activity of people physical laws - the steady repeating objective laws existing in the nature are established. The most important laws establish connection between physical sizes for what it is necessary these conducted ranks to measure. Measurement of physical size is the action which is carried out by means of measuring apparatuses for a finding of value of physical size in accepted units. Units of physical sizes can be chosen any way but then has arisen нут difficulties at their comparison. Therefore it is expedient to enter the system of units covering units of all physical sizes.
For construction of system of units any way choose units for several physical sizes not dependent from each other. These units are called as the cores. Other sizes and their units are deduced from the laws connecting these sizes and their units with the cores. They are called as derivatives.
Now the System International (SI) which is under construction on seven basic units - metre, kg, second, ampere, кельвин, моль, кандела - and two additional - a radian and стерадиан is obligatory to application in scientific, and also in the educational literature.
Metre () - length of the way passed by light in vacuum for 1/299792458 with. Kg (kg) - the weight equal to weight of the international prototype of kg (платиноиридиевого the cylinder stored in the International bureau of measures and scales in Sevre, near Paris).
Second () - time equal to 9 192631770 periods of radiation, corresponding to transition between two superthin levels of the basic condition of atom of caesium-133.
The ampere () - force of not changing current which at passage on двук to parallel rectilinear conductors of infinite length also it is insignificant малоп the cross-section section, located in vacuum on distance of 1 m one from another creates the force equal 2⋅10-7 Н on each metre of length between these conductors.
Calvin () - 1/273,16 part of thermodynamic temperature threefold sharpen waters.
Моль (моль) - quantity of substance of the system containing as much of structural elements, how many atoms contain in нуклиде 12С in weight 0,012 kg.
Кандела (кд) - force of light in the set direction of the source which is letting out monochromatic radiation by frequency 540 ' Ю12 Hz, power which force of light in this direction makes 1/683 Vt/compare
The radian (is glad) - a corner between two radiuses of a circle the length of an arch between which is equal to radius.
Стерадиан (ср) - a space angle with top in the sphere centre, cutting out from a surface of sphere the area equal to the area of a square with the party, sphere equal to radius.
For an establishment of derivative units use the physical laws connecting them with basic units. For example, from the formula of uniform directly linear movement v=st (s - the passed way, t - time) derivative unit of speed turns out equal 1 km/s.
Mechanics - a part of physics which studies laws of mechanical movement and the reasons causing or changing this movement. Mechanical movement is a change eventually a relative positioning of bodies or their parts.
Mechanics development as sciences begins from III century BC when Ancient Greek scientist Archimedes (287-212 BC) has formulated the law of balance of the lever and laws of balance of floating bodies. Mechanics Organic laws are established by the Italian physicist and the astronomer G.Galileem (1564-1642) and definitively formulated by English scientist I.Newton (1643-1727).
The mechanics Galilee-Newton is called as classical mechanics. In it laws of movement of the macroscopical bodies which speeds are small in comparison with a velocity of light in vacuum are studied. Laws of movement of macroscopical bodies with speeds, comparable with a speed with, are studied by the relativistic mechanics based on the special theory of a relativity, formulated by A.Einstein (1879-1955). For the description of movement of microscopic bodies (separate atoms and elementary particles) laws of classical mechanics are inapplicable - they are replaced with laws of quantum mechanics.
In the first part of our course we will study mechanics Galilee-Newton, i.e. to consider movement of macroscopical bodies with speeds, is considerable smaller speeds with. In the classical mechanics the space and time concept developed by I.Newton and dominating in natural sciences throughout XVII-XIX centuries of the Mechanic Galilee-Newton is standard considers space and time as objective forms of existence of a matter, but in a separation from each other and from movement of material bodies that corresponded to level of knowledge of that time.
The mechanics shares on three sections: 1) kinematics; 2) dynamics; 3) a statics.
The kinematics studies movement of bodies, without considering the reason which cause this movement.
Dynamics studies laws of movement of bodies and the reason which cause or change this movement.
The statics studies laws of balance of system of bodies. If laws of movement of bodies from them it is possible to establish and balance laws are known. Therefore statics laws separately from laws of dynamics of the physicist does not consider.