Energy sign in physics. Notations in physics are units of measurement of physical quantities. State standard of the USSR

In mathematics, symbols are used throughout the world to simplify and shorten text. Below is a list of the most common mathematical notations, corresponding commands in TeX, explanations and examples of use. In addition to those indicated... ... Wikipedia

A list of specific symbols used in mathematics can be seen in the article Table of mathematical symbols Mathematical notation (“the language of mathematics”) is a complex graphic system of notation used to present abstract ... ... Wikipedia

A list of sign systems (notation systems, etc.) used by human civilization, with the exception of writing systems, for which there is a separate list. Contents 1 Criteria for inclusion in the list 2 Mathematics ... Wikipedia

Paul Adrien Maurice Dirac Paul Adrien Maurice Dirac Date of birth: 8& ... Wikipedia

Dirac, Paul Adrien Maurice Paul Adrien Maurice Dirac Date of birth: August 8, 1902(... Wikipedia

Gottfried Wilhelm Leibniz Gottfried Wilhelm Leibniz ... Wikipedia

This term has other meanings, see Meson (meanings). Meson (from other Greek μέσος middle) boson of strong interaction. In the Standard Model, mesons are composite (not elementary) particles consisting of even... ... Wikipedia

Nuclear physics ... Wikipedia

Alternative theories of gravity are usually called theories of gravity that exist as alternatives to the general theory of relativity (GTR) or significantly (quantitatively or fundamentally) modify it. Towards alternative theories of gravity... ... Wikipedia

Alternative theories of gravity are usually called theories of gravity that exist as alternatives to the general theory of relativity or significantly (quantitatively or fundamentally) modify it. Alternative theories of gravity are often... ... Wikipedia

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This article or section needs revision. Please improve the article in accordance with the rules for writing articles. Physical... Wikipedia

A physical quantity is a quantitative characteristic of an object or phenomenon in physics, or the result of a measurement. The size of a physical quantity is the quantitative determination of a physical quantity inherent in a specific material object, system, ... ... Wikipedia

This term has other meanings, see Photon (meanings). Photon Symbol: sometimes... Wikipedia

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Books

Hydraulics. Textbook and workshop for academic bachelor's degree, V.A. Kudinov. The textbook outlines the basic physical and mechanical properties of liquids, issues of hydrostatics and hydrodynamics, provides the basics of the theory of hydrodynamic similarity and mathematical modeling...
Hydraulics 4th ed., trans. and additional Textbook and workshop for academic bachelor's degree, Eduard Mikhailovich Kartashov. The textbook outlines the basic physical and mechanical properties of liquids, issues of hydrostatics and hydrodynamics, provides the basics of the theory of hydrodynamic similarity and mathematical modeling...

Each measurement is a comparison of the measured quantity with another homogeneous quantity, which is considered unitary. Theoretically, the units for all quantities in physics can be chosen to be independent of each other. But this is extremely inconvenient, since for each value one should enter its own standard. In addition, in all physical equations that reflect the relationship between different quantities, numerical coefficients would arise.

The main feature of the currently used systems of units is that there are certain relationships between units of different quantities. These relationships are established by the physical laws (definitions) that relate the measured quantities to each other. Thus, the unit of speed is chosen in such a way that it is expressed in terms of units of distance and time. When selecting speed units, the speed definition is used. The unit of force, for example, is established using Newton's second law.

When constructing a specific system of units, several physical quantities are selected, the units of which are set independently of each other. Units of such quantities are called basic. The units of other quantities are expressed in terms of the basic ones, they are called derivatives.

Table of units of measurement "Space and time"

Physical quantity	Symbol		Unit change physical led	Description	Notes
	*l, s, d*			The extent of an object in one dimension.
	S	square meter		The extent of an object in two dimensions.
Volume, capacity	V	cubic meter		The extent of an object in three dimensions.	extensive quantity
	t			Duration of the event.
Flat angle	α , φ			The amount of change in direction.
Solid angle	α , β , γ	steradian		Part of space
Linear speed	v	meter per second		The speed of changing body coordinates.
Linear acceleration	*a, w*	meters per second squared		The rate of change in the speed of an object.
Angular velocity	ω	radians per second	rad/s =	Angle change rate.
Angular acceleration	ε	radian per second squared	rad/s 2 =	Rate of change of angular velocity

Table of units of measurement "Mechanics"

Physical quantity	Symbol	Unit of measurement of physical quantity	Unit change physical led	Description	Notes
	m	kilogram		A quantity that determines the inertial and gravitational properties of bodies.	extensive quantity
Density	ρ	kilogram per cubic meter	kg/m 3	Mass per unit volume.	intensive quantity
Surface density	ρA	Mass per unit area.	kg/m2	Ratio of body mass to surface area
Linear density	ρ l	Mass per unit length.		Ratio of body mass to its linear parameter
Specific volume	v	cubic meter per kilogram	m 3 /kg	Volume occupied by a unit mass of a substance
Mass flow	Q m	kilogram per second		The mass of a substance that passes through a given cross-sectional area of a flow per unit time
Volume flow	Q v	cubic meter per second	m 3 /s	Volume flow of liquid or gas
	P	kilogram-meter per second	kg m/s	Product of mass and speed of a body.
Momentum	L	kilogram-meter squared per second	kg m 2 /s	A measure of the rotation of an object.	conserved quantity
	J	kilogram meter squared	kg m 2	A measure of the inertia of an object during rotation.	tensor quantity
Strength, weight	*F, Q*			An external cause of acceleration acting on an object.
Moment of power	M	newton meter	(kg m 2 /s 2)	The product of a force and the length of a perpendicular drawn from a point to the line of action of the force.
Impulse force	I	newton second		Product of force and the duration of its action
Pressure, mechanical stress	p , σ		Pa = ( kg/(m s 2))	Force per unit area.	intensive quantity
	A		J= (kg m 2 /s 2)	Dot product of force and displacement.
	*E, U*		J =(kg m 2 /s 2)	The ability of a body or system to do work.	extensive, conserved quantity, scalar
Power	N		W =(kg m 2 /s 3)	Rate of change of energy.

Table of units of measurement "Periodic phenomena, oscillations and waves"

Physical quantity	Symbol	Unit of measurement of physical quantity	Unit change physical led	Description	Notes
	T			The period of time during which the system makes one complete oscillation
Batch frequency	*v, f*			The number of repetitions of an event per unit of time.
Cyclic (circular) frequency	ω	radians per second	rad/s	Cyclic frequency of electromagnetic oscillations in an oscillatory circuit.
Rotation frequency	n	second to the minus first power		A periodic process equal to the number of complete cycles completed per unit of time.
Wavelength	λ			The distance between two points in space closest to each other at which the oscillations occur in the same phase.
Wave number	k	meter to the minus first power		Spatial wave frequency

Units table " Thermal phenomena"

Physical quantity	Symbol	Unit of measurement of physical quantity	Unit change physical led	Description	Notes
Temperature	T			The average kinetic energy of the object's particles.	Intensive value
Temperature coefficient	α	kelvin to the minus first power		Dependence of electrical resistance on temperature
Temperature gradient	*gradT*	kelvin per meter		Change in temperature per unit length in the direction of heat propagation.
Heat (amount of heat)	Q		J =(kg m 2 /s 2)	Energy transferred from one body to another by non-mechanical means
Specific heat	q	joule per kilogram	J/kg	The amount of heat that must be supplied to a substance taken at its melting point in order to melt it.
Heat capacity	C	joule per kelvin		The amount of heat absorbed (released) by a body during the heating process.
Specific heat	c	joule per kilogram kelvin	J/(kg K)	Heat capacity of a unit mass of a substance.
Entropy	S	joule per kilogram	J/kg	A measure of the irreversible dissipation of energy or the uselessness of energy.

Units table " Molecular physics"

Physical quantity	Symbol	Unit of measurement of physical quantity	Unit change physical led	Description	Notes
Quantity of substance	*v, n*		mole	The number of similar structural units that make up a substance.	Extensive value
Molar mass	M , μ	kilogram per mole	kg/mol	The ratio of the mass of a substance to the number of moles of that substance.
Molar energy	*H pier*	joule per mole	J/mol	Energy of a thermodynamic system.
Molar heat capacity	*with a pier*	joule per mole kelvin	J/(mol K)	The heat capacity of one mole of a substance.
Molecular concentration	*c, n*	meter to the minus third power		The number of molecules contained in a unit volume.
Mass concentration	ρ	kilogram per cubic meter	kg/m 3	The ratio of the mass of a component contained in a mixture to the volume of the mixture.
Molar concentration	*with a pier*	mole per cubic meter	mol/m 3
Ion mobility	IN , μ	square meter per volt second	m 2 /(V s)	The proportionality coefficient between the drift velocity of carriers and the applied external electric field.

Units table " Electricity and magnetism"

Physical quantity	Symbol	Unit of measurement of physical quantity	Unit change physical led	Description	Notes
Current strength	I			Charge flowing per unit time.
Current Density	j	ampere per square meter		The strength of the electric current flowing through a surface element of unit area.	Vector quantity
Electric charge	Q, q		Cl =(A s)	The ability of bodies to be a source of electromagnetic fields and to take part in electromagnetic interaction.	extensive, conserved quantity
Electric dipole moment	p	coulomb meter		Electrical properties of a system of charged particles in the sense of the field it creates and the effect of external fields on it.
Polarization	P	pendant per square meter	C/m 2	Processes and states associated with the separation of any objects, mainly in space.
Voltage	U			Change in potential energy per unit charge.
Potential, EMF	*φ, σ*			The work of external forces (non-Coulomb) to move a charge.
	E	volt per meter		The ratio of the force F acting on a stationary point charge placed at a given point in the field to the magnitude of this charge q
Electrical capacity	C			A measure of a conductor's ability to store electrical charge
Electrical resistance	*R,r*		Ohm =(m 2 kg/(s 3 A 2))	resistance of an object to the passage of electric current
Electrical resistivity	ρ			The ability of a material to prevent the passage of electric current
Electrical conductivity	G			The ability of a body (medium) to conduct electric current
Magnetic induction	B			Vector quantity, which is the force characteristic of the magnetic field	Vector quantity
Magnetic flux	F		(kg/(s 2 A))	A value that takes into account the intensity of the magnetic field and the area it occupies.
Magnetic field strength	H	ampere per meter		The difference between the magnetic induction vector B and the magnetization vector M	Vector quantity
Magnetic moment	p m	ampere square meter		A quantity characterizing the magnetic properties of a substance
Magnetization	J	ampere per meter		A quantity characterizing the magnetic state of a macroscopic physical body.	vector quantity
Inductance	L			The proportionality coefficient between the electric current flowing in any closed circuit and the total magnetic flux
Electromagnetic energy	N		J =(kg m 2 /s 2)	Energy contained in an electromagnetic field
Volumetric energy density	w	joule per cubic meter	J/m 3	Electric field energy of a capacitor
Active power	P			AC power
Reactive power	Q			A quantity characterizing the loads created in electrical devices by fluctuations in the energy of the electromagnetic field in the alternating current circuit
Full power	S	watt-ampere		Total power, taking into account its active and reactive components, as well as deviations of the current and voltage waveforms from harmonic

Units table " Optics, electromagnetic radiation"

Physical quantity	Symbol	Unit of measurement of physical quantity	Unit change physical led	Description	Notes
The power of light	*J,I*			The amount of light energy emitted in a given direction per unit time.	Luminous, extensive value
Light flow	F			Physical quantity characterizing the amount of “light” power in the corresponding radiation flux
Light energy	Q	lumen-second		Physical quantity characterizes the ability of energy transferred by light to cause visual sensations in a person
Illumination	E			The ratio of the luminous flux incident on a small area of a surface to its area.
Luminosity	M	lumen per square meter	lm/m 2	Luminous quantity representing luminous flux
	*L, B*	candela per square meter	cd/m2	Luminous intensity emitted per unit surface area in a specific direction
Radiation energy	*E,W*		J =(kg m 2 /s 2)	Energy transferred by optical radiation

Table of units of measurement "Acoustics"

Physical quantity	Symbol	Unit of measurement of physical quantity	Unit change physical led	Description	Notes
Sound pressure	p			Variable excess pressure arising in an elastic medium when a sound wave passes through it
Volume velocity	*c, V*	cubic meter per second	m 3 /s	The ratio of the volume of raw materials supplied to the reactor per hour to the volume of catalyst
Sound speed	*v, u*	meter per second		Velocity of propagation of elastic waves in a medium
Sound intensity	l	watt per square meter	W/m2	A quantity characterizing the power transferred by a sound wave in the direction of propagation	scalar physical quantity
Acoustic impedance	Z a , R a	pascal second per cubic meter	Pa s/m 3	The ratio of the amplitude of sound pressure in a medium to the vibrational speed of its particles when a sound wave passes through the medium
Mechanical resistance	Rm	newton second per meter	N s/m	Indicates the force required to move a body at each frequency

Units table " Atomic and nuclear physics. Radioactivity"

Physical quantity	Symbol	Unit of measurement of physical quantity	Unit change physical led	Description	Notes
Mass (rest mass)	m	kilogram		The mass of an object at rest.
Mass defect	Δ	kilogram		A quantity expressing the influence of internal interactions on the mass of a composite particle
Elementary electric charge	e			The minimum portion (quantum) of electric charge observed in nature in free long-lived particles
Communication energy	E St		J =(kg m 2 /s 2)	The difference between the energy of a state in which the constituent parts of the system are infinitely distant
Half-life, average lifetime	*T, τ*			The time during which the system decays in the approximate ratio of 1/2
Effective cross section	σ	square meter		A quantity characterizing the probability of interaction of an elementary particle with an atomic nucleus or another particle
Nuclide activity		becquerel		A value equal to the ratio of the total number of decays of radioactive nuclide nuclei in the source to the decay time
Energy of ionizing radiation	*E,W*		J =(kg m 2 /s 2)	Type of energy released by atoms in the form of electromagnetic waves (gamma or x-rays) or particles
Absorbed dose of ionizing radiation	D			The dose at which 1 joule of ionizing radiation energy is transferred to a mass of 1 kg
Equivalent dose of ionizing radiation	H , D eq			Absorbed dose of any ionizing radiation equal to 100 erg per 1 gram of irradiated substance
Exposure dose of X-ray and gamma radiation	X	pendant per kilogram	C/kg	ratio of the total electric charge of ions of the same sign from external gamma radiation

Physics notation with multiple letters

To designate some quantities, several letters or individual words or abbreviations are sometimes used. Thus, a constant value in the formula is often denoted as

The differential is indicated by a small letter

Before the name of the quantity, for example .

Special symbols

For ease of writing and reading, it is customary among physicists to use special symbols that characterize certain phenomena and properties.

In physics, it is customary to use not only formulas that are used in mathematics, but also specialized brackets.

Diacritics

Diacritics are added to the symbol of a physical quantity to indicate certain differences. Below, diacritics have been added to the letter x as an example.

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Cheat sheet with formulas in physics for the Unified State Exam

and more (may be needed for grades 7, 8, 9, 10 and 11).

First, a picture that can be printed in a compact form.

Mechanics

Pressure P=F/S
Density ρ=m/V
Pressure at liquid depth P=ρ∙g∙h
Gravity Ft=mg
5. Archimedean force Fa=ρ f ∙g∙Vt
Equation of motion for uniformly accelerated motion

X=X 0 + υ 0 ∙t+(a∙t 2)/2 S=( υ 2 -υ 0 2) /2a S=( υ +υ 0) ∙t /2

Velocity equation for uniformly accelerated motion υ =υ 0 +a∙t
Acceleration a=( υ -υ 0)/t
Circular speed υ =2πR/T
Centripetal acceleration a= υ 2/R
Relationship between period and frequency ν=1/T=ω/2π
Newton's II law F=ma
Hooke's law Fy=-kx
Law of Gravity F=G∙M∙m/R 2
Weight of a body moving with acceleration a P=m(g+a)
Weight of a body moving with acceleration а↓ Р=m(g-a)
Friction force Ftr=µN
Body momentum p=m υ
Force impulse Ft=∆p
Moment of force M=F∙ℓ
Potential energy of a body raised above the ground Ep=mgh
Potential energy of an elastically deformed body Ep=kx 2 /2
Kinetic energy of the body Ek=m υ 2 /2
Work A=F∙S∙cosα
Power N=A/t=F∙ υ
Efficiency η=Ap/Az
Oscillation period of a mathematical pendulum T=2π√ℓ/g
Oscillation period of a spring pendulum T=2 π √m/k
Equation of harmonic vibrations Х=Хmax∙cos ωt
Relationship between wavelength, its speed and period λ= υ T

Molecular physics and thermodynamics

Amount of substance ν=N/Na
Molar mass M=m/ν
Wed. kin. energy of monatomic gas molecules Ek=3/2∙kT
Basic MKT equation P=nkT=1/3nm 0 υ 2
Gay-Lussac's law (isobaric process) V/T =const
Charles's law (isochoric process) P/T =const
Relative humidity φ=P/P 0 ∙100%
Int. energy ideal. monatomic gas U=3/2∙M/µ∙RT
Gas work A=P∙ΔV
Boyle–Mariotte law (isothermal process) PV=const
Amount of heat during heating Q=Cm(T 2 -T 1)
Amount of heat during melting Q=λm
Amount of heat during vaporization Q=Lm
Amount of heat during fuel combustion Q=qm
Equation of state of an ideal gas PV=m/M∙RT
First law of thermodynamics ΔU=A+Q
Efficiency of heat engines η= (Q 1 - Q 2)/ Q 1
Efficiency is ideal. engines (Carnot cycle) η= (T 1 - T 2)/ T 1

Electrostatics and electrodynamics - formulas in physics

Coulomb's law F=k∙q 1 ∙q 2 /R 2
Electric field strength E=F/q
Electrical tension point charge field E=k∙q/R 2
Surface charge density σ = q/S
Electrical tension fields of an infinite plane E=2πkσ
Dielectric constant ε=E 0 /E
Potential energy of interaction. charges W= k∙q 1 q 2 /R
Potential φ=W/q
Point charge potential φ=k∙q/R
Voltage U=A/q
For a uniform electric field U=E∙d
Electric capacity C=q/U
Electric capacity of a flat capacitor C=S∙ ε ∙ε 0 /d
Energy of a charged capacitor W=qU/2=q²/2С=CU²/2
Current strength I=q/t
Conductor resistance R=ρ∙ℓ/S
Ohm's law for the circuit section I=U/R
Laws of the last. connections I 1 =I 2 =I, U 1 +U 2 =U, R 1 +R 2 =R
Laws parallel. conn. U 1 =U 2 =U, I 1 +I 2 =I, 1/R 1 +1/R 2 =1/R
Electric current power P=I∙U
Joule-Lenz law Q=I 2 Rt
Ohm's law for a complete circuit I=ε/(R+r)
Short circuit current (R=0) I=ε/r
Magnetic induction vector B=Fmax/ℓ∙I
Ampere power Fa=IBℓsin α
Lorentz force Fl=Bqυsin α
Magnetic flux Ф=BSсos α Ф=LI
Law of electromagnetic induction Ei=ΔФ/Δt
Induction emf in a moving conductor Ei=Вℓ υ sinα
Self-induction EMF Esi=-L∙ΔI/Δt
Coil magnetic field energy Wm=LI 2 /2
Oscillation period no. circuit T=2π ∙√LC
Inductive reactance X L =ωL=2πLν
Capacitance Xc=1/ωC
Effective current value Id=Imax/√2,
Effective voltage value Uд=Umax/√2
Impedance Z=√(Xc-X L) 2 +R 2

Optics

Law of light refraction n 21 =n 2 /n 1 = υ 1 / υ 2
Refractive index n 21 =sin α/sin γ
Thin lens formula 1/F=1/d + 1/f
Lens optical power D=1/F
max interference: Δd=kλ,
min interference: Δd=(2k+1)λ/2
Differential grid d∙sin φ=k λ

The quantum physics

Einstein's formula for the photoelectric effect hν=Aout+Ek, Ek=U z e
Red border of the photoelectric effect ν k = Aout/h
Photon momentum P=mc=h/ λ=E/s

Physics of the atomic nucleus