Interesting names from mechanics and physics. Modern Russian
There are two kinds of electric charges, positive and negative.
Charges can be transferred (for example, by direct contact) from one body to another. Unlike body mass, electric charge is not an inherent characteristic of a given body. The same body in different conditions may have different charges.
Like charges repel, unlike charges attract. This shows the fundamental difference between electromagnetic forces and gravitational ones. Gravitational forces are always forces of attraction.
One of the fundamental laws of nature is the experimentally established law of conservation of electric charge. In an isolated system, the algebraic sum of the charges of all bodies remains constant:
q 1 + q 1 + q 3 + ... + q n= const.
The law of conservation of electric charge states that in a closed system of bodies processes of the birth or disappearance of charges of only one sign cannot be observed.
From the modern point of view, charge carriers are elementary particles. All ordinary bodies are composed of atoms, which include positively charged protons, negatively charged electrons and neutral particles - neutrons. Protons and neutrons are part of atomic nuclei, electrons form the electron shell of atoms. The electric charges of the proton and electron modulo are exactly the same and equal to the elementary charge e:
e\u003d 1.602177 10 -19 C ≈ 1.6 10 -19 C
In a neutral atom, the number of protons in the nucleus is equal to the number of electrons in the shell. This number is called the atomic number. An atom of a given substance can lose one or more electrons or gain an extra electron. In these cases, the neutral atom turns into a positively or negatively charged ion.
A charge can be transferred from one body to another only in portions containing an integer number of elementary charges. Thus, the electric charge of the body is a discrete quantity.
Physical quantities that can only take on a discrete series of values are called quantized. elementary charge e is a quantum (smallest portion) of electric charge.
It should be noted that in modern elementary particle physics, the existence of so-called quarks, particles with a fractional charge, is assumed. However, quarks have not yet been observed in the free state.
In conventional laboratory experiments, an electrometer is used to detect and measure electric charges - a device consisting of a metal rod and an arrow that can rotate around a horizontal axis. The arrowhead is insulated from the metal case. When a charged body comes into contact with the rod of an electrometer, electric charges of the same sign are distributed along the rod and the arrow. The forces of electrical repulsion cause the arrow to turn at a certain angle, by which one can judge the charge transferred to the rod of the electrometer.
Examination tickets in physics 2006-2007 ac. year
Grade 9
Ticket number 1.mechanical movement. Path. Speed, Acceleration
mechanical movement- change in the position of the body in space relative to other bodies over time.
Path- the length of the trajectory along which the body moves for some time. Denoted by the letter s and measured in meters (m). Calculated according to the formula
Speed is a vector quantity equal to the ratio of the path to the time for which this path has been traveled. Determines both the speed of movement and its direction at a given time. Denoted by a letter and measured in meters per second (). Calculated according to the formula
Acceleration with uniformly accelerated motion is a vector quantity equal to the ratio of the change in speed to the time interval during which this change occurred. Determines the rate of change of speed in magnitude and direction. Denoted by letter a or and is measured in meters per second squared (). Calculated according to the formula
Ticket number 2.The phenomenon of inertia. Newton's first law. Strength and composition of forces. Newton's second law
The phenomenon of maintaining the speed of a body in the absence of the action of other bodies is called inertia.
Newton's first law: there are frames of reference with respect to which bodies keep their speed unchanged if they are not acted upon by other bodies.
Frames of reference where the law of inertia is satisfied are called inert.
Frames of reference where the law of inertia is not fulfilled - non-inert.
Strength- vector quantity. And it is a measure of the interaction of bodies. Denoted by letter F or and is measured in newtons (N)
A force that produces the same effect on a body as several simultaneously acting forces is called resultant of these forces.
The resultant of forces directed along one straight line in one direction is directed in the same direction, and its module is equal to the sum of the modules of the component forces.
The resultant of forces directed along one straight line in opposite directions is directed towards the greater force in absolute value, and its module is equal to the difference between the modules of the component forces.
The greater the resultant of the forces applied to the body, the greater the acceleration of the body.
When the force is halved, the acceleration is also halved, i.e.
Means, the acceleration with which a body of constant mass moves is directly proportional to the force applied to this body, as a result of which acceleration occurs.
When the body weight is doubled, the acceleration is halved, i.e.
Means, the acceleration with which a body moves with a constant force is inversely proportional to the mass of that body.
The quantitative relationship between body mass, acceleration, and the resultant of the forces applied to the body is called Newton's second law.
Second Newton's law: acceleration of the body is directly proportional to the resultant forces applied to the body and inversely proportional to its mass.
Mathematically, Newton's second law is expressed by the formula:
Ticket number 3. Newton's third law. Pulse. Law of conservation of momentum. Explanation of jet propulsion based on the law of conservation of momentum
Newton's third law: the forces with which two bodies act on each other are equal in magnitude and opposite in direction.
Mathematically, Newton's third law is expressed as follows:
body momentum- a vector quantity equal to the product of the mass of the body and its speed. It is denoted by a letter and is measured in kilograms per meters per second (). Calculated according to the formula
law of conservation of momentum: the sum of the momenta of the bodies before the interaction is equal to the sum after the interaction. Let's consider jet propulsion based on the motion of a balloon with a jet of air coming out of it. According to the law of conservation of momentum, the total momentum of a system consisting of two bodies must remain the same as it was before the start of the outflow of air, i.e. equal to zero. Therefore, the ball begins to move in the direction opposite to the air jet with the same speed that its momentum is equal to the modulus of the air jet momentum.
Ticket number 4.Gravity. Free fall. Acceleration free fall. Law of gravity
Gravity- the force with which the Earth attracts the body to itself. Denoted or
Free fall- the movement of bodies under the influence of gravity.
In a given place on the Earth, all bodies, regardless of their masses and other physical characteristics, free fall with the same acceleration. This acceleration is called free fall acceleration and is denoted by the letter or . It
The law of universal gravitation: any two bodies are attracted to each other with a force directly proportional to the mass of each of them and inversely proportional to the square of the distance between them.
G \u003d 6.67 10 -11 N m 2 / kg 2
G - Gravitational constant
Ticket number 5. Elastic force. Explanation of the device and principle of operation of the dynamometer. Friction force. Friction in nature and technology
The force that arises in the body as a result of its deformation and tends to return the body to its original position is called elastic force. Designated . It is found according to the formula
Dynamometer- a device for measuring force.
The main part of the dynamometer is a steel spring, which is given a different shape depending on the purpose of the device. The device of the simplest dynamometer is based on the comparison of any force with the elastic force of the spring.
When one body comes into contact with another, an interaction occurs that prevents their relative motion, which is called friction. And the force that characterizes this interaction is called friction force. There is static friction, sliding friction and rolling friction.
Without the friction of rest, neither people nor animals could walk on the earth, because. When we walk, we push off the ground with our feet. If there were no friction, objects would slip out of the hands. The force of friction stops the car when braking, but without static friction, it would not be able to start moving. In many cases, friction is harmful and must be dealt with. To reduce friction, the contact surfaces are made smooth, and a lubricant is introduced between them. To reduce the friction of the rotating shafts of machines and machine tools, they are supported on bearings.
Ticket number 6. Pressure. Atmosphere pressure. Pascal's law. Law of Archimedes
The value equal to the ratio of the force acting perpendicular to the surface to the area of this surface is called pressure. It is denoted by the letter or and is measured in pascals (Pa). Calculated according to the formula
Atmosphere pressure- this is the pressure of the entire thickness of the air on the earth's surface and the bodies located on it.
Atmospheric pressure equal to the pressure of a column of mercury 760 mm high at a temperature is called normal atmospheric pressure.
Normal atmospheric pressure is 101300Pa = 1013hPa.
Every 12m the pressure decreases by 1mm. rt. Art. (or by 1.33hPa)
Pascal's law: the pressure exerted on a liquid or gas is transmitted to any point equally in all directions.
Archimedes' law: a body immersed in a liquid (or gas, or plasma) is subjected to a buoyant force (called the Archimedes force)
where ρ is the density of the liquid (gas), is the acceleration of free fall, and V is the volume of the submerged body (or the part of the volume of the body below the surface). The buoyant force (also called the Archimedean force) is equal in absolute value (and opposite in direction) to the force of gravity acting on the volume of liquid (gas) displaced by the body, and is applied to the center of gravity of this volume.
It should be noted that the body must be completely surrounded by the liquid (or intersected by the surface of the liquid). So, for example, the law of Archimedes cannot be applied to a cube that lies at the bottom of the tank, hermetically touching the bottom.
Ticket number 7.Force work. Kinetic and potential energy. Law of conservation of mechanical energy
Mechanical work is done only when a force acts on the body and it moves.
mechanical work directly proportional to the applied force and directly proportional to the distance traveled. It is denoted by the letter or and is measured in joules (J). Calculated according to the formula
Energy - a physical quantity showing how much work a body can do. Energy is measured in joules (J).
Potential energy called energy, which is determined by the mutual position of interacting bodies or parts of the same body. Indicated by the letter or . Calculated according to the formula
The energy possessed by a body as a result of its motion is called kinetic energy. Indicated by the letter or . Calculated according to the formula
The law of conservation of mechanical energy:
In the absence of forces such as friction, mechanical energy does not arise from nothing and cannot disappear anywhere.
Ticket number 8.Mechanical vibrations. mechanical waves. Sound.Fluctuations in nature and technology
A movement that repeats itself after a certain period of time is called oscillatory.
Oscillations that occur only due to the initial supply of energy are called free vibrations Physics The concept of time in classical thermodynamics Abstract >> Philosophy
He puts time first major concepts physics, followed by space, place... ideas about space is introduced in physics high energy concept physical vacuum as a kind of...
Physical terms
Acoustics(from Greek. akustikos- auditory) - in a broad sense - a branch of physics that studies elastic waves from the lowest frequencies to the highest (1012–1013 Hz); in a narrow sense - the doctrine of sound. General and theoretical acoustics are engaged in the study of the laws of radiation and propagation elastic waves in various environments, as well as their interaction with the environment. The sections of acoustics include electroacoustics, architectural acoustics and building acoustics, atmospheric acoustics, geoacoustics, hydroacoustics, physics and technology of ultrasound, psychological and physiological acoustics, musical acoustics.
Astrospectroscopy- a branch of astronomy that studies spectra celestial bodies in order to determine the physical and chemical properties of these bodies, including the speed of their movement, from the spectral characteristics.
Astrophysics the branch of astronomy that studies physical state and chemical composition celestial bodies and their systems, interstellar and intergalactic media, as well as the processes occurring in them. Main sections of astrophysics: physics of planets and their satellites, physics of the Sun, physics of stellar atmospheres, interstellar medium, theory internal structure stars and their evolution. Problems of the structure of superdense objects and related processes (capture of matter from environment, accretion disks, etc.) and the problems of cosmology are considered by relativistic astrophysics.
Atom(from Greek. atomos- indivisible) - the smallest particle of a chemical element that retains its properties. In the center of the atom is a positively charged nucleus, in which almost the entire mass of the atom is concentrated; electrons move around, forming electron shells, the dimensions of which (~108 cm) determine the dimensions of the atom. The nucleus of an atom is made up of protons and neutrons. The number of electrons in an atom is equal to the number of protons in the nucleus (the charge of all the electrons of the atom is equal to the charge of the nucleus), the number of protons is equal to the ordinal number of the element in periodic system. Atoms can gain or donate electrons, becoming negatively or positively charged ions. Chemical properties atoms are determined mainly by the number of electrons in the outer shell; Atoms combine chemically to form molecules. An important characteristic of an atom is its internal energy, which can only take certain (discrete) values corresponding to the stable states of the atom, and changes only abruptly through a quantum transition. Absorbing a certain portion of energy, the atom goes into an excited state (more high level energy). From an excited state, an atom, emitting a photon, can go to a state with a lower energy (to a lower energy level). The level corresponding to the minimum energy of an atom is called the ground level, the rest are called excited. Quantum transitions determine the atomic absorption and emission spectra, individual for atoms of all chemical elements.
Atomic mass is the mass of an atom, expressed in atomic mass units. The atomic mass is less than the sum of the masses of the particles that make up the atom (protons, neutrons, electrons) by an amount determined by the energy of their interaction.
atomic nucleus- positively charged central part an atom, in which practically all the mass of an atom is concentrated. Consists of protons and neutrons (nucleons). The number of protons determines the electric charge atomic nucleus and the atomic number Z of the atom in the Periodic system of elements. The number of neutrons is equal to the difference between the mass number and the number of protons. The volume of an atomic nucleus changes in proportion to the number of nucleons in the nucleus. In diameter, heavy atomic nuclei reach 10-12 cm. The density of nuclear matter is about 1014 g/cm3.
Aerolite- an obsolete name for a stone meteorite.
white dwarfs are compact stellar remnants of the evolution of low-mass stars. These objects are characterized by masses comparable to the mass of the Sun (2 1030 kg); radii comparable to the radius of the Earth (6400 km) and densities of the order of 106 g/cm3. The name "white dwarfs" is associated with the small size (compared to the typical size of stars) and the white color of the first discovered objects. of this type determined by their high temperature.
Block- a detail in the form of a wheel with a groove around the circumference for a thread, chain, rope. They are used in machines and mechanisms to change the direction of the force (fixed block), to obtain a gain in strength or path (movable block).
fireball- a large and exceptionally bright meteor.
Vacuum(from lat. vacuum- void) - the state of the gas at pressures p, lower than atmospheric. There are low vacuum (in vacuum devices and installations, it corresponds to the pressure range p above 100 Pa), medium (0.1 Pa< p < 100 Па), высокий (10-5 Па < p < 0,1 Па), и сверхвысокий (p < 10-5 Па). Понятие «вакуум» применимо к газу в откаченном объеме и в свободном пространстве, напр. к космосу.
Rotating moment is a measure of an external action that changes the angular velocity of a rotating body. Torque M rr is equal to the sum of the moments of all forces acting on the body about the axis of rotation and is related to the angular acceleration of the body e by the equality M vr =
I e, where I is the moment of inertia of the body about the axis of rotation.
Universe- the entire existing material world, unlimited in time and space and infinitely diverse in the forms that matter takes in the process of its development. The Universe studied by astronomy is a part of the material world, which is accessible to research by astronomical means corresponding to the achieved level of development of science (sometimes this part of the Universe is called the Metagalaxy).
Computer Engineering – 1
) a set of technical and mathematical means (computers, devices, devices, programs, etc.) used for mechanization and automation of computing and information processing processes. It is used in solving scientific and engineering problems associated with a large amount of calculations, in automatic and automated control systems, in accounting, planning, forecasting and economic evaluation, in making scientifically sound decisions, processing experimental data, in information retrieval systems, etc. . 2
) A branch of technology involved in the development, manufacture and operation of computers, devices and devices.
Gas(French gas, from Greek. chaos- chaos) - the state of aggregation of matter, in which the kinetic energy of the thermal motion of its particles (molecules, atoms, ions) significantly exceeds the potential energy of interactions between them, and therefore, the particles move freely, uniformly filling in the absence of external fields the entire volume provided to them .
Galaxy(from Greek. galaktikos- milky) - a star system (spiral galaxy) to which the Sun belongs. The galaxy contains at least 1011 stars (with a total mass of 1011 solar masses), interstellar matter (gas and dust, whose mass is a few percent of the mass of all stars), cosmic rays, magnetic fields, radiation (photons). Most stars occupy a lenticular volume with a diameter of approx. 30 thousand pc, concentrating to the plane of symmetry of this volume (galactic plane) and to the center (flat subsystem of the Galaxy). Smaller part stars fills an almost spherical volume with a radius of approx. 15 thousand pc (spherical subsystem of the Galaxy), concentrating towards the center (core) of the Galaxy, which is located from the Earth in the direction of the constellation Sagittarius. The sun is located near the galactic plane at a distance of approx. 10 thousand pc from the center of the Galaxy. For a terrestrial observer, stars concentrating towards the galactic plane merge into a visible picture Milky Way.
Helium(lat. Helium) – chemical element with atomic number 2, atomic mass 4.002602. Belongs to the group of inert, or noble, gases (group VIIIA of the periodic system).
Hyperons(from Greek. hyper –
above, above) –
heavy unstable elementary particles with a mass greater than the mass of a nucleon (proton and neutron), having a baryon charge and a long lifetime compared to the "nuclear time" (~ 10-23 sec).
Gyroscope(from gyro... and... osprey) is a rapidly rotating rigid body, the axis of rotation of which can change its direction in space. A gyroscope has a number of interesting properties that are observed in rotating celestial bodies, in artillery shells, in a children's top, in turbine rotors installed on ships, etc. Various devices or devices widely used in modern technology for automatic control of aircraft movement, sea vessels, missiles, torpedoes and other objects, to determine the horizon or geographic meridian, to measure the translational or angular speeds of moving objects (for example, missiles), and much more.
Globules– gas-dust formations with dimensions of several tenths of a parsec; are observed in the form dark spots against a background of light nebulae. Perhaps the globules are the regions where stars are born.
Gravity field(field of gravitation) - a physical field created by any physical objects; through the gravitational field, the gravitational interaction of bodies is carried out.
Pressure- a physical quantity that characterizes the intensity of normal (perpendicular to the surface) forces F, with which one body acts on the surface S of another (for example, the foundation of a building on the ground, liquid on the walls of a vessel, etc.). If the forces are uniformly distributed along the surface, then the pressure is P = F/S. Pressure is measured in Pa or in kgf / cm2 (the same as at), as well as in mm Hg. st., atm, etc.
Dynamics(from the Greek dynamis - force) - a section of mechanics that studies the movement of bodies under the action of forces applied to them.
discreteness(from lat. discretus- divided, intermittent) - discontinuity; opposed to continuity. For example, a discrete change in a quantity over time is a change that occurs at certain intervals of time (jumps).
Dissociation(from lat. dissociation- separation) - the disintegration of a particle (molecule, radical, ion) into several simpler particles. The ratio of the number of particles that decayed during dissociation to their total number before decay is called the degree of dissociation. Depending on the nature of the impact that causes dissociation, there are thermal dissociation, photodissociation, electrolytic dissociation, dissociation under the action of ionizing radiation.
Inch(from goll. duim, lit. - thumb) - 1
) submultiple unit of length in the system of English measures. 1 inch = 1/12 foot = 0.0254 m. 2
) Russian odometric unit of length. 1 inch = 1/12 feet = 10 lines = 2.54 cm.
Liquid- the state of aggregation of a substance, combining the features of a solid state (conservation of volume, a certain tensile strength) and a gaseous state (shape variability). A liquid is characterized by a short-range order in the arrangement of particles (molecules, atoms) and a small difference in the kinetic energy of the thermal motion of molecules and their potential energy of interaction. The thermal motion of liquid molecules consists of oscillations around equilibrium positions and relatively rare jumps from one equilibrium position to another, which is associated with the fluidity of the liquid.
Law- a necessary, essential, stable, recurring relationship between phenomena in nature and society. The concept of "law" is related to the concept of essence. There are three main groups of laws: specific, or private (for example, the law of addition of velocities in mechanics); common to large groups phenomena (for example, the law of conservation and transformation of energy, the law of natural selection); general, or universal, laws. The knowledge of the law is the task of science.
Wien's radiation law– sets the distribution of energy in the spectrum of a black body depending on temperature. A special case of Planck's law of radiation for high frequencies. Bred in 1893 by V. Wine.
Planck's law of radiation– establishes the distribution of energy in the spectrum of a completely black body (equilibrium thermal radiation). Bred by M. Planck in 1900.
Radiation electromagnetic- the process of formation of free electromagnetic field; radiation is also called the free electromagnetic field itself. Radiate rapidly moving charged particles (eg, bremsstrahlung, synchrotron radiation, radiation of variable dipoles, quadrupoles and higher-order multipoles). The atom and other atomic systems radiate at quantum transitions from excited states to states of lower energy.
Insulator(from the French isoler - to separate) - 1
) a substance with a very high electrical resistivity (dielectric). 2
) A device that prevents the formation of electrical contact and in many cases also provides a mechanical connection between parts of electrical equipment located under different electrical potentials; made of dielectrics in the form of disks, cylinders, etc. 3
) In radio engineering, insulators are called a segment of a short-circuited 2-wire or coaxial line, which has a high electrical resistance at a given frequency.
isotopes(from iso... and Greek. topos- place) - varieties of chemical elements in which the nuclei of atoms differ in the number of neutrons, but contain the same number of protons and therefore occupy the same place in the periodic system of elements. There are stable (stable) isotopes and radioactive isotopes. The term was proposed by F. Soddy in 1910.
Pulse – 1
) a measure of mechanical motion (the same as the amount of motion). All forms of matter have momentum, including electromagnetic and gravitational fields; 2
) impulse of force - a measure of the action of force over a certain period of time; is equal to the product of the average value of the force by the time of its action; 3
) wave impulse - a single perturbation propagating in space or a medium, for example: a sound impulse - a sudden and rapidly disappearing increase in pressure; light pulse ( special case electromagnetic) - short-term ( 0.01 s) emission of light by a source of optical radiation; 4
) electrical impulse - a short-term deviation of voltage or current from a certain constant value.
Inertial frame of reference - a reference system in which the law of inertia is valid: a material point, when no forces act on it (or mutually balanced forces act), is at rest or uniform rectilinear motion.
ions(from Greek. ion- going) - electrically charged particles formed from an atom (molecule) as a result of the loss or addition of one or more electrons. Positively charged ions are called cations, negatively charged ions are called anions. The term was proposed by M. Faraday in 1834.
Dwarfs- stars of small sizes (from 1 to 0.01 solar radii) and low luminosities (from 1 to 10-4 solar luminosities) with a mass M from 1 to 0.1 solar masses. There are many eruptive stars among dwarfs. From ordinary, or red, dwarfs, white dwarfs differ sharply in their structure and properties.
Secondary quantization– a method for studying quantum systems of many or an infinite number particles (or quasiparticles); is especially important in quantum field theory, which considers systems with a varying number of particles. In the method of quantization of the secondary state of the system, it is described using occupation numbers. The change of state is interpreted as the processes of birth and destruction of particles.
Quantum mechanics(wave mechanics) - a theory that establishes the method of description and the laws of motion of microparticles in given external fields; one of the main branches of quantum theory. Quantum mechanics for the first time made it possible to describe the structure of atoms and understand their spectra, to establish the nature chemical bond, explain the periodic system of elements, etc. Since the properties of macroscopic bodies are determined by the motion and interaction of the particles that form them, the laws of quantum mechanics underlie the understanding of most macroscopic phenomena. Thus, quantum mechanics made it possible to understand many properties of solids, to explain the phenomena of superconductivity, ferromagnetism, superfluidity, and much more; quantum mechanical laws underlie nuclear energy, quantum electronics, etc. In contrast to the classical theory, all particles in quantum mechanics act as carriers of both corpuscular and wave properties, which do not exclude, but complement each other. The wave nature of electrons, protons and other "particles" is confirmed by experiments on particle diffraction. The corpuscular-wave dualism of matter required a new approach to describing the state of physical systems and their changes over time. The state of a quantum system is described by a wave function, the square of the modulus of which determines the probability of this state and, consequently, the probabilities for the values physical quantities, characterizing it; It follows from quantum mechanics that not all physical quantities can simultaneously have exact values (see the Uncertainty Principle). wave function obeys the superposition principle, which explains, in particular, particle diffraction. Distinctive feature quantum theory - the discreteness of possible values for a number of physical quantities: the energy of electrons in atoms, the angular momentum and its projection on an arbitrary direction, etc.; in the classical theory all these quantities can change only continuously. A fundamental role in quantum mechanics is played by Planck's constant ћ - one of the main scales of nature, delimiting the areas of phenomena that can be described classical physics(in these cases we can assume j = 0), from areas for the correct interpretation of which quantum theory is necessary. Non-relativistic (pertaining to small particle velocities compared to the speed of light) quantum mechanics is a complete, logically consistent theory that is fully consistent with experience for that range of phenomena and processes in which there is no birth, annihilation or mutual transformation of particles.
Quantum theory– combines quantum mechanics, quantum statistics and quantum theory fields.
Quarks are hypothetical fundamental particles, of which modern ideas, all hadrons consist (baryons - from three quarks, mesons - from a quark and an antiquark). Quarks have a spin of 1/2, a baryon charge of 1/3, electric charges of -2/3 and +1/3 of the proton's charge, and a specific quantum number "color". Experimentally (indirectly) discovered 6 types ("flavors") of quarks: u, d, s, c, b, t. They were not observed in the free state.
Kinetic energy is the energy of the mechanical system, which depends on the speed of movement of its constituent parts. In classical mechanics, kinetic energy material point masses m moving at a speed v, is equal to 1/2 mv 2.
Oxygen(lat. Ohygenium) is a chemical element with atomic number 8, atomic mass 15.9994. In the periodic system of elements, Mendeleev is located in the second period in the VIA group.
classical mechanics- studies the movement of macroscopic bodies with speeds that are small compared to the speed of light, based on Newton's laws.
Fluctuations - movements (changes of state) with varying degrees of repeatability. When the pendulum oscillates, its deviations in one direction and the other from the vertical position are repeated. When the spring pendulum oscillates –
weight hanging on a spring –
its deviations up and down from some average position are repeated. When oscillating in an electrical circuit with capacitance C and inductance L, the magnitude and sign of the charge are repeated q on each plate of the capacitor. Pendulum swings occur because: 1) gravity returns the deflected pendulum to its equilibrium position; 2) having returned to the equilibrium position, the pendulum, having a speed, continues to move (by inertia) and again deviates from the equilibrium position in the direction opposite to the one from which it came.
Colorimetry(from lat. color- color and Greek. metreo– measure), methods of measurement and quantitative expression colors are based on the definition of color coordinates in the selected system of 3 primary colors.
Coma- distortion of the image in optical systems, due to which the point of the object takes the form of an asymmetric spot.
Comets(from Greek. cometes, lit. - long-haired), body solar system, move along highly elongated orbits, at considerable distances from the Sun they look like faintly luminous oval spots, and as they approach the Sun, they have a “head” and “tail”. The central part of the head is called the nucleus. The diameter of the core is 0.5-20 km, the mass is 1011-1019 kg, the core is an icy body - a conglomerate of frozen gases and dust particles. The tail of a comet consists of molecules (ions) of gases and dust particles escaping from the nucleus under the action of sunlight; the length of the tail can reach tens of millions of kilometers. The most famous periodic comets are Halley (period R 76 years old), Enke ( R 3.3 years), Schwassmann - Wachmann (the comet's orbit lies between the orbits of Jupiter and Saturn). While passing through perihelion in 1986, Halley's comet was examined by spacecraft.
Compton Effect- discovered by A. Compton (1922) elastic scattering of electromagnetic radiation of small wavelengths (X-ray and gamma radiation) on free electrons, accompanied by an increase in the wavelength l. The Compton effect contradicts the classical theory, according to which l should not change during such scattering. The Compton effect confirmed the correctness of quantum ideas about electromagnetic radiation as a stream of photons and can be considered as an elastic collision of two "particles" - a photon and an electron, in which the photon transfers part of its energy (and momentum) to the electron, as a result of which its frequency decreases, and l increases .
Convection(from lat. convection- bringing, delivery) - the movement of macroscopic parts of the medium (gas, liquid), leading to the transfer of mass, heat, and other physical quantities. There are natural (free) convection caused by the inhomogeneity of the medium (temperature and density gradients), and forced convection caused by external mechanical action on the medium. The formation of clouds is associated with convection in the Earth's atmosphere, and granulation is associated with convection on the Sun.
Electric circuit(circuit of an electrical circuit) - any closed path passing through several branches of an electrical circuit. Sometimes the term "electrical circuit" is used as a synonym for the term "oscillating circuit".
Coriolis force(named after the French scientist G. Corey-olis) –
one of the forces of inertia introduced to take into account the influence of the rotation of a moving frame of reference on the relative motion of a material point. The Coriolis force is equal to the product of the mass of a point and its Coriolis acceleration and is directed opposite to this acceleration.
Coefficient(from lat. co- jointly and efficiency- producing) - a multiplier, usually expressed in numbers. If the product contains one or more variable (or unknown) quantities, then the coefficient for them is also called the product of all constants, including those expressed by letters. Many coefficients in physical laws have special names, for example, friction coefficient, light absorption coefficient.
red giants- stars with low effective temperatures (3000-4000 K) and very large radii (10-100 times the radius of the Sun). The maximum radiation energy falls on the red and infrared parts of the spectrum. The luminosity of red giants is approximately 100 times greater than the luminosity of the Sun.
Lagrange equations -1
) in hydromechanics - the equations of motion of a liquid medium, written in Lagrange variables, which are the coordinates of the particles of the medium. From the Lagrange equation, the law of motion of particles of the medium is determined in the form of dependences of coordinates on time, and trajectories, velocities and accelerations of particles are found from them. 2
) In general mechanics, equations used to study the motion of a mechanical system, in which parameters that are independent of each other are chosen for the quantities that determine the position of the system, are called generalized coordinates. First obtained by J. Lagrange in 1760
Magnetism(from Greek. magnetis– magnet) – 1
) a branch of physics that studies the interaction of moving electrically charged particles (bodies) or particles (bodies) with a magnetic moment, carried out magnetic field. 2
) The general name of the manifestations of this interaction. Elementary particles (electrons, protons, etc.) participate in magnetic interactions, electric currents and magnetized bodies that have a magnetic moment. For elementary particles, the magnetic moment can be spin and orbital. The magnetism of atoms of molecules and macroscopic bodies is ultimately determined by the magnetism of elementary particles. Depending on the nature of the interaction of particles-carriers of the magnetic moment, substances can exhibit ferromagnetism, ferrimagnetism, antiferromagnetism, paramagnetism, diamagnetism, and other types of magnetism.
A magnetic field- one of the forms of the electromagnetic field. The magnetic field is created by moving electric charges and spin magnetic moments of atomic carriers of magnetism (electrons, protons, etc.). Full description electric and magnetic fields and their relationship give Maxwell's equations.
Weight- one of the main physical characteristics of matter, which determines its inert and gravitational properties. In classical mechanics, mass is equal to the ratio of the force acting on the body to the acceleration it causes (Newton's 2nd law) - in this case, the mass is called inertial; in addition, the mass creates a gravitational field - gravitational, or heavy, mass. Inertial and heavy masses are equal to each other (equivalence principle).
Mesoatom- an atom-like system in which the forces of electrostatic attraction bind the positive nucleus with one (or several) negatively charged muons (muonic atom) or hadrons (hadron atom). The mesoatom can also contain electrons.
meteorites- small bodies of the solar system that fall to Earth from interplanetary space. The mass of one of the largest meteors - Goba meteorite - approx. 60,000 kg. There are iron and stone meteorites.
Method(from Greek. methodos- the path of research, theory, teaching) - a way to achieve a goal, solve a specific problem; a set of techniques or operations of practical or theoretical development (cognition) of reality.
Mechanics(from the Greek mechanike - the art of building machines) - the science of the mechanical movement of material bodies (that is, the change in the relative position of bodies or their parts in space over time) and the interactions between them. Classical mechanics is based on Newton's laws. The methods of mechanics study the motions of any material bodies (except for microparticles) with speeds that are small compared to the speed of light. Movements of bodies with velocities close to the speed of light are considered in the theory of relativity, and the movement of microparticles - in quantum mechanics. Depending on the motion of which objects is considered, the mechanics of a material point and systems of material points are distinguished, mechanics solid body, continuum mechanics. Mechanics is divided into statics, kinematics and dynamics. The laws of mechanics are used to calculate machines, mechanisms, building structures, vehicles, space aircraft etc. The founders of mechanics - G. Galileo, I. Newton and others.
microparticles– particles of very small mass; these include elementary particles, atomic nuclei, atoms, molecules.
Milky Way– 1
) a dimly luminous band crossing the starry sky. Represents great amount visually indistinguishable stars concentrating towards the main plane of the Galaxy. The Sun is located near this plane, so that most of the stars of the Galaxy are projected onto the celestial sphere within a narrow band - the Milky Way. 2
) Actually the name of the Galaxy.
Molecule(novolat. molecule, reduce. from lat. moles- mass) - a microparticle formed from atoms and capable of independent existence. It has a constant composition of its constituent atomic nuclei and a fixed number of electrons and has a set of properties that make it possible to distinguish molecules of one type from molecules of another. The number of atoms in a molecule can be different: from two to hundreds of thousands (eg, in a protein molecule); the composition and arrangement of atoms in a molecule is conveyed by the chemical formula. Molecular structure substances are determined by X-ray diffraction analysis, electron diffraction, mass spectrometry, electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) and other methods.
Molecular mass(molecular weight) is the mass of a molecule, expressed in atomic mass units. Almost equal to the sum of the masses of all the atoms that make up the molecule. Quantities molecular weight are used in chemical, physical and chemical-technical calculations.
Moment of inertia- a quantity that characterizes the distribution of masses in the body and, along with the mass, is a measure of the inertia of the body during non-translational motion.
Moment of momentum(kinetic moment, angular momentum, angular momentum) - a measure of the mechanical movement of a body or system of bodies relative to any center (point) or axis. To calculate moment of momentum To material point (body), the same formulas are valid as for calculating the moment of force, if we replace the force vector in them with the momentum vector mv, in particular K 0 = [ r× mv]. The sum of the moments of the momentum of all points of the system about the center (axis) is called the main moment of the momentum of the system (kinetic moment) about this center (axis). With the rotational motion of a rigid body, the main moment of momentum about the axis of rotation z body is expressed by the product of the moment of inertia I z to the angular velocity w of the body, i.e. To Z= I zw.
Muons– unstable elementary particles with spin 1/2, lifetime 2.210-6 sec and a mass approximately 207 times the mass of an electron.
Absolute zero temperature - the lowest of all possible temperature values. At absolute zero, matter has no thermal energy.
Annihilation - a process in which a particle and its antiparticle, colliding, mutually annihilate each other.
Antiparticle - each particle of matter has a corresponding antiparticle. When a particle and an antiparticle collide, they annihilate, as a result of which energy is released and other particles are born.
Atom is the smallest particle of ordinary matter. An atom consists of a tiny nucleus (composed of protons and neutrons) and electrons revolving around it.
white dwarf - a stable cold star, which is in equilibrium due to the fact that, due to the Pauli exclusion principle, repulsive forces act between electrons.
Big Bang - Singularity at the time of the creation of the Universe.
big cotton - Singularity at the end point of the existence of the Universe.
The weight - the force with which the gravitational field acts on the body. Body weight is proportional to body weight, but does not coincide with it.
virtual particle - in quantum mechanics - a particle that cannot be registered directly, but whose existence is confirmed by measurable effects.
Gamma radiation - electromagnetic radiation with a very short wavelength, emitted at radioactive decay or at collisions of elementary particles.
Geodetic ~ the shortest (or longest) path between two points.
Naked singularity A singularity in space-time that is not inside a black hole.
event horizon is the boundary of a black hole.
Gravitational interaction - the weakest of the four fundamental interactions, which has a large radius of action. All particles of matter participate in the gravitational interaction.
Wavelength - the distance between two adjacent wave crests or between two adjacent wave troughs.
Law of energy conservation - the law of science, according to which energy (or its mass equivalent) can neither be created nor destroyed.
Quantum - the minimum portion, which measures the emission or absorption of waves.
Quantum mechanics - a theory developed on the basis of Planck's quantum mechanical principle and Heisenberg's uncertainty principle.
Planck's quantum mechanical principle (Planck's law of radiation) is that light (or any other classical waves) can be emitted or absorbed only in discrete portions - quanta - with an energy proportional to their frequency.
Quark - an elementary (charged) particle participating in a strong interaction. Protons and neutrons are each made up of three quarks.When a high density of nuclear matter is reached, for example, during a strong explosion, nucleons (protons and neutrons) lose their boundaries. It turns out a new state of matter - without hadrons - quark-gluon plasma. Presumably, this was the state of matter in the first moments after the Big Bang.
Confinement - confinement, confinement of colored quarks and gluons inside hadrons.
Coordinates - numbers that determine the position of a point in space and time.
Space censorship – the assumption about the inadmissibility of bare singularities.
Cosmological constant - a mathematical auxiliary quantity introduced by Einstein in order for space-time to acquire a tendency to expand.
Cosmology A science that studies the universe as a whole.
Redshift Reddening of the light emitted by a star moving away from us caused by the Doppler effect.
A magnetic field - a field that creates magnetic forces. Now the magnetic field and the electric field are combined into an electromagnetic field.
Weight - the amount of substance contained in the body. A measure of a body's inertia or the degree of its resistance to acceleration.
imaginary time is time measured in imaginary units.
Neutrino - the lightest (possibly massless) elementary particle of matter, participating only in weak and gravitational interactions.
Neutron - an uncharged particle, very close in properties to a proton. Neutrons make up more than half of the particles that make up most atomic nuclei.
neutron star - a cold star that exists due to the repulsion of neutrons due to the Pauli principle.
General theory of relativity - A theory created by Einstein, which is based on the assumption that the laws of science should be the same for all observers, regardless of how these observers move. In general relativity, the existence of gravitational interaction is explained by the curvature of four-dimensional space-time.
Primordial black hole - a black hole that arose at a very early stage in the development of the universe.
Positron is the antiparticle (positively charged) of the electron.
Field - something that exists at all points in space and time, in contrast to a particle, which exists only at one point at a time.
Chandrasekhar limit is the maximum possible mass of a stable cold star, above which the star must collapse into a black hole.
Pauli exclusion principle – two identical particles with spin 1/2 cannot (within the limits given by the uncertainty principle) simultaneously have the same positions in space and different velocities.
Proportionality - the statement "X is proportional to Y" means that when Y is multiplied by some number, X is multiplied by the same number. The statement "X is inversely proportional to Y" means that when Y is multiplied by some number, X is divided by the same number.
Spatial Dimension - any of the three space-like dimensions of space-time, i.e. any dimension other than temporal.
space-time is a four-dimensional space, the points of which correspond to events.
Proton is a positively charged particle. Protons form about half of all particles that make up the nuclei of most atoms.
Radioactivity - spontaneous transformation of one atomic nucleus into another.
light second (light year) - the distance traveled by light in one second (one year).
light cone – a surface in space-time that limits the possible directions of light rays passing through a given event.
Strong interaction is the strongest and shortest-range of the four fundamental forces. Due to the strong interaction, quarks are held inside protons and neutrons, and protons and neutrons, when brought together, form atomic nuclei.
Singularity - a point in space-time at which its curvature becomes infinite.
Weak interaction is the second weakest of the four known interactions. Has a very short range. All particles of matter take part in the weak interaction, but the particles that carry the interaction do not participate in it.
Event - a point in space-time, which is determined by the position in space and time.
Spectrum - splitting of a wave (for example, electromagnetic) into frequency components.
Special theory of relativity - Einstein's theory, the starting point of which is that the laws of science should be the same for all freely moving observers, regardless of their speeds.
Spin (spin - rotate, spin) - an internal property of the particle associated with its rotation around its own axis.
Stationary state - a state that does not change with time: a ball rotating at a constant speed is in a stationary state, because, despite the rotation, at every moment it looks the same.
Singularity theorem - a theorem in which it is proved that under certain conditions a singularity must exist and that, in particular, the beginning of the Universe must be a singularity.
grand unified theory - a theory that combines electromagnetic, strong and weak interactions.
Acceleration - the rate of change of the speed of any object.
particle accelerator - a device that, with the help of electromagnets, makes it possible to accelerate moving charged particles, constantly increasing their energy.
No border condition - a view according to which the Universe is finite, but has no boundaries (in imaginary time).
Phase – for a wave, the position of a point in a cycle at a given point in time: a measure of whether a point is on a crest, a trough, or somewhere in between.
Background of microwave radiation - radiation generated by the glow of a hot early universe(called relic). It is now experiencing such a strong redshift that it does not register as light, but as microwaves (radio waves with centimeter wavelengths).
Photon is a quantum of light.
Particle-wave dualism - the idea underlying quantum mechanics that there is no difference between particles and waves, particles can sometimes behave like waves, and waves can behave like particles.
Frequency - for a wave, this is the number of complete cycles per second.
Cherenkov radiation - emission of light by a charged particle when it moves in a substance with a constant speed exceeding the speed of light propagation in this substance.
Black hole - a region of space-time from which nothing, not even light, can get out, because the action of gravity is extremely strong in it.
Electric charge - property of a particle due to which it repels (or attracts) other particles having a charge of the same (or opposite) sign.
Electromagnetic interaction - the interaction that occurs between particles that have electric charge. The second strongest of the four fundamental forces.
Electron - a particle with a negative electric charge and circulating in an atom around the nucleus.
Elementary particle - a particle that is considered indivisible.
The Energy of Grand Unified Theory is the energy above which the electromagnetic, weak and strong interactions are expected to become indistinguishable.
Energy of the electroweak theory is the energy (about 100 GeV), above which the differences between electromagnetic and weak interactions disappear.
Doppler effect – change in the frequency of waves when their source and observer move relative to each other.
Nuclear fusion - the process of collision of two nuclei and their subsequent merger into one heavier nucleus.
Nucleus - the central part of the atom, which consists only of protons and neutrons held in the nucleus by strong interaction.