It's no secret that there are special designations for quantities in any science. Letter designations in physics prove that this science is no exception in terms of identifying quantities using special symbols. There are a lot of basic quantities, as well as their derivatives, each of which has its own symbol. So, letter designations in physics are discussed in detail in this article.
Physics and basic physical quantities
Thanks to Aristotle, the word physics began to be used, since it was he who first used this term, which at that time was considered synonymous with the term philosophy. This is due to the generality of the object of study - the laws of the Universe, more specifically, how it functions. As you know, in the XVI-XVII centuries the first scientific revolution took place, it was thanks to it that physics was singled out as an independent science.
Mikhail Vasilyevich Lomonosov introduced the word physics into the Russian language through the publication of a textbook translated from German - the first textbook on physics in Russia.
So, physics is a branch of natural science devoted to the study of the general laws of nature, as well as matter, its movement and structure. There are not so many basic physical quantities as it might seem at first glance - there are only 7 of them:
- length,
- weight,
- time,
- current,
- temperature,
- amount of substance
- the power of light.
Of course, they have their own letter designations in physics. For example, the symbol m is chosen for mass, and T for temperature. Also, all quantities have their own unit of measurement: the intensity of light is candela (cd), and the unit of measurement for the amount of substance is the mole.
Derived physical quantities
There are much more derivative physical quantities than the main ones. There are 26 of them, and often some of them are attributed to the main ones.
So, area is a derivative of length, volume is also a derivative of length, speed is a derivative of time, length, and acceleration, in turn, characterizes the rate of change in speed. Impulse is expressed in terms of mass and velocity, force is the product of mass and acceleration, mechanical work depends on force and length, and energy is proportional to mass. Power, pressure, density, surface density, linear density, amount of heat, voltage, electrical resistance, magnetic flux, moment of inertia, moment of momentum, moment of force - they all depend on mass. Frequency, angular velocity, angular acceleration are inversely proportional to time, and electric charge is directly dependent on time. Angle and solid angle are derived quantities from length.
What is the symbol for stress in physics? Voltage, which is a scalar quantity, is denoted by the letter U. For speed, the designation is in the form of the letter v, for mechanical work - A, and for energy - E. Electric charge is usually denoted by the letter q, and magnetic flux is F.
SI: general information
The International System of Units (SI) is a system of physical units based on the International System of Units, including the names and designations of physical units. It was adopted by the General Conference on Weights and Measures. It is this system that regulates the letter designations in physics, as well as their dimension and units of measurement. For designation, letters of the Latin alphabet are used, in some cases - Greek. It is also possible to use special characters as a designation.
Conclusion
So, in any scientific discipline there are special designations for various kinds of quantities. Naturally, physics is no exception. There are a lot of letter designations: force, area, mass, acceleration, voltage, etc. They have their own designations. There is a special system called the International System of Units. It is believed that the basic units cannot be mathematically derived from others. Derived quantities are obtained by multiplying and dividing from the basic ones.
Building drawings is not an easy task, but without it in the modern world there is no way. After all, in order to make even the most ordinary object (a tiny bolt or nut, a book shelf, the design of a new dress, and the like), you first need to make the appropriate calculations and draw a drawing of the future product. However, it is often made by one person, and another is engaged in the manufacture of something according to this scheme.
In order to avoid confusion in understanding the depicted object and its parameters, the conventions of length, width, height and other quantities used in design are accepted all over the world. What are they? Let's find out.
Quantities
Area, height and other designations of a similar nature are not only physical, but also mathematical quantities.
Their single letter designation (used by all countries) was established in the middle of the twentieth century by the International System of Units (SI) and is used to this day. It is for this reason that all such parameters are indicated in Latin, and not in Cyrillic letters or Arabic script. In order not to create separate difficulties, when developing standards for design documentation in most modern countries, it was decided to use almost the same symbols that are used in physics or geometry.
Any school graduate remembers that depending on whether a two-dimensional or three-dimensional figure (product) is shown in the drawing, it has a set of basic parameters. If there are two dimensions - this is the width and length, if there are three - the height is also added.
So, for starters, let's find out how to correctly indicate the length, width, height in the drawings.
Width
As mentioned above, in mathematics, the quantity under consideration is one of the three spatial dimensions of any object, provided that its measurements are made in the transverse direction. So what is the famous width? It is designated with the letter "B". This is known all over the world. Moreover, according to GOST, the use of both capital and lowercase Latin letters is permissible. The question often arises as to why such a letter was chosen. After all, usually the reduction is made according to the first Greek or English name of the value. In this case, the width in English will look like "width".
Probably, the point here is that this parameter was originally most widely used in geometry. In this science, describing figures, often the length, width, height are denoted by the letters "a", "b", "c". According to this tradition, when choosing, the letter "B" (or "b") was borrowed by the SI system (although non-geometric symbols began to be used for the other two dimensions).
Most believe that this was done in order not to confuse the width (designated by the letter "B" / "b") with the weight. The fact is that the latter is sometimes referred to as "W" (short for the English name weight), although the use of other letters ("G" and "P") is also acceptable. According to the international standards of the SI system, the width is measured in meters or multiples (longitudinal) of their units. It is worth noting that in geometry it is sometimes also acceptable to use "w" to denote width, but in physics and other exact sciences, this designation is usually not used.
Length
As already mentioned, in mathematics, length, height, width are three spatial dimensions. Moreover, if the width is a linear dimension in the transverse direction, then the length is in the longitudinal direction. Considering it as a quantity of physics, one can understand that this word means a numerical characteristic of the length of lines.
In English, this term is called length. It is because of this that this value is indicated by the capital or lowercase initial letter of this word - “L”. Like width, length is measured in meters or their multiples (longitudinal) units.
Height
The presence of this value indicates that one has to deal with a more complex - three-dimensional space. Unlike length and width, height quantifies the size of an object in the vertical direction.
In English, it is written as "height". Therefore, according to international standards, it is designated by the Latin letter "H" / "h". In addition to the height, in the drawings, sometimes this letter also acts as a depth designation. Height, width and length - all of these parameters are measured in meters and their multiples and submultiples (kilometers, centimeters, millimeters, etc.).
Radius and Diameter
In addition to the parameters considered, when drawing up drawings, one has to deal with others.
For example, when working with circles, it becomes necessary to determine their radius. This is the name of a segment that connects two points. The first one is the center. The second is located directly on the circle itself. In Latin, this word looks like "radius". Hence the lowercase or capital "R"/"r".
When drawing circles, in addition to the radius, one often has to deal with a phenomenon close to it - the diameter. It is also a line segment connecting two points on a circle. However, it must pass through the center.
Numerically, the diameter is equal to two radii. In English, this word is written like this: "diameter". Hence the abbreviation - a large or small Latin letter "D" / "d". Often the diameter in the drawings is indicated with a crossed out circle - “Ø”.
Although this is a common abbreviation, it should be borne in mind that GOST provides for the use of only the Latin "D" / "d".
Thickness
Most of us remember school math lessons. Even then, teachers said that it was customary to designate such a quantity as area with the Latin letter “s”. However, according to generally accepted standards, a completely different parameter is recorded in the drawings in this way - thickness.
Why is that? It is known that in the case of height, width, length, the designation with letters could be explained by their spelling or tradition. That's just the thickness in English looks like "thickness", and in the Latin version - "crassities". It is also not clear why, unlike other quantities, the thickness can be denoted only by a lowercase letter. The "s" designation is also used to describe the thickness of pages, walls, ribs, and so on.
Perimeter and area
Unlike all the quantities listed above, the word "perimeter" did not come from Latin or English, but from the Greek language. It is derived from "περιμετρέο" ("to measure the circumference"). And today this term has retained its meaning (the total length of the borders of the figure). Subsequently, the word got into the English language ("perimeter") and was fixed in the SI system in the form of an abbreviation with the letter "P".
Area is a quantity showing a quantitative characteristic of a geometric figure that has two dimensions (length and width). Unlike everything listed earlier, it is measured in square meters (as well as in submultiples and multiples of them). As for the letter designation of the area, it differs in different areas. For example, in mathematics, this is the Latin letter “S”, familiar to everyone since childhood. Why so - there is no information.
Some unknowingly think it has to do with the English spelling of the word "square". However, in it the mathematical area is "area", and "square" is the area in the architectural sense. By the way, it is worth remembering that "square" is the name of the geometric figure "square". So you should be careful when studying drawings in English. Due to the translation of "area" in some disciplines, the letter "A" is used as a designation. In rare cases, "F" is also used, but in physics this letter means a quantity called "force" ("fortis").
Other common abbreviations
The designations of height, width, length, thickness, radius, diameter are the most used in drawing up drawings. However, there are other quantities that are also often present in them. For example, lowercase "t". In physics, this means "temperature", however, according to the GOST of the Unified System for Design Documentation, this letter is a pitch (of helical springs, and the like). However, it is not used when it comes to gears and threads.
The capital and lowercase letter "A" / "a" (according to all the same standards) in the drawings is used to indicate not the area, but the center-to-center and center-to-center distance. In addition to various values, in the drawings it is often necessary to designate angles of different sizes. For this, it is customary to use lowercase letters of the Greek alphabet. The most used are "α", "β", "γ" and "δ". However, others can be used as well.
What standard defines the letter designation of length, width, height, area and other quantities?
As mentioned above, so that there is no misunderstanding when reading the drawing, representatives of different peoples have adopted common standards for letter designation. In other words, if you are in doubt about the interpretation of a particular abbreviation, look at GOSTs. Thus, you will learn how to correctly indicate the height, width, length, diameter, radius, and so on.
Symbols are commonly used in mathematics to simplify and shorten text. Below is a list of the most common mathematical notation, the corresponding commands in TeX, explanations and usage examples. 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 ("language of mathematics") is a complex graphic notation system used to present abstract ... ... Wikipedia
A list of sign systems (notation systems, etc.) used by human civilization, with the exception of scripts, 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 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 average) boson of strong interaction. In the Standard Model, mesons are composite (not elementary) particles consisting of an even ... ... Wikipedia
Nuclear physics ... Wikipedia
It is customary to call alternative theories of gravity theories of gravity that exist as alternatives to the general theory of relativity (GR) or substantially (quantitatively or fundamentally) modifying it. To alternative theories of gravity ... ... Wikipedia
It is customary to call alternative theories of gravity theories of gravity that exist as alternatives to the general theory of relativity or substantially (quantitatively or fundamentally) modifying it. To alternative theories of gravity often ... ... Wikipedia
It is necessary to check the quality of the translation and bring the article in line with the stylistic rules of Wikipedia. You can help ... Wikipedia
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 certainty of a physical quantity inherent in a particular material object, system, ... ... Wikipedia
This term has other meanings, see Photon (meanings). Photon Symbol: sometimes ... Wikipedia
This term has other meanings, see Born. Max Born Max Born ... Wikipedia
Examples of various physical phenomena Physics (from other Greek φύσις ... Wikipedia
Photon Symbol: sometimes emitted photons in a coherent laser beam. Composition: Family ... Wikipedia
This term has other meanings, see Mass (meanings). Mass Dimension M SI units kg ... Wikipedia
CROCUS Nuclear reactor is a device in which a controlled nuclear chain reaction is carried out, accompanied by the release of energy. The first nuclear reactor was built and launched in December 1942 at ... Wikipedia
Books
- Hydraulics. Textbook and workshop for academic baccalaureate, Kudinov V.A.
- Hydraulics 4th ed., trans. and additional Textbook and workshop for academic baccalaureate, Eduard Mikhailovich Kartashov. The textbook outlines the basic physical and mechanical properties of liquids, issues of hydrostatics and hydrodynamics, gives the basics of the theory of hydrodynamic similarity and mathematical modeling ...
Cheat sheet with formulas in physics for the exam
and not only (may need 7, 8, 9, 10 and 11 classes).
For starters, a picture that can be printed in a compact form.
Mechanics
- Pressure P=F/S
- Density ρ=m/V
- Pressure at the depth of the liquid P=ρ∙g∙h
- Gravity Ft=mg
- 5. Archimedean force Fa=ρ w ∙g∙Vt
- Equation of motion for uniformly accelerated motion
X=X0 + υ 0∙t+(a∙t 2)/2 S=( υ 2 -υ 0 2) /2а 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 universal gravitation F=G∙M∙m/R 2
- The weight of a body moving with acceleration a P \u003d m (g + a)
- The weight of a body moving with acceleration a ↓ P \u003d m (g-a)
- Friction force Ffr=µN
- Body momentum p=m υ
- Force impulse Ft=∆p
- Moment M=F∙ℓ
- Potential energy of a body raised above the ground Ep=mgh
- Potential energy of 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 the mathematical pendulum T=2π√ℓ/g
- Oscillation period of a spring pendulum T=2 π √m/k
- The equation of harmonic oscillations Х=Хmax∙cos ωt
- Relationship of the 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 equation of MKT P=nkT=1/3nm 0 υ 2
- Gay-Lussac law (isobaric process) V/T =const
- Charles' law (isochoric process) P/T =const
- Relative humidity φ=P/P 0 ∙100%
- Int. ideal energy. monatomic gas U=3/2∙M/µ∙RT
- Gas work A=P∙ΔV
- Boyle's law - Mariotte (isothermal process) PV=const
- The amount of heat during heating Q \u003d Cm (T 2 -T 1)
- The amount of heat during melting Q=λm
- The amount of heat during vaporization Q=Lm
- The amount of heat during fuel combustion Q=qm
- The equation of state for an ideal gas is PV=m/M∙RT
- First law of thermodynamics ΔU=A+Q
- Efficiency of heat engines η= (Q 1 - Q 2) / Q 1
- Ideal efficiency. engines (Carnot cycle) η \u003d (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
- Email tension. field of a point charge E=k∙q/R 2
- Surface charge density σ = q/S
- Email tension. fields of the 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
- Capacitance of a flat capacitor C=S∙ ε ∙ε 0/d
- Energy of a charged capacitor W=qU/2=q²/2С=CU²/2
- Current I=q/t
- Conductor resistance R=ρ∙ℓ/S
- Ohm's law for the circuit section I=U/R
- The laws of the last compounds I 1 \u003d I 2 \u003d I, U 1 + U 2 \u003d U, R 1 + R 2 \u003d R
- Parallel laws. conn. U 1 \u003d U 2 \u003d U, I 1 + I 2 \u003d I, 1 / R 1 + 1 / R 2 \u003d 1 / R
- Electric current power P=I∙U
- Joule-Lenz law Q=I 2 Rt
- Ohm's law for a complete chain I=ε/(R+r)
- Short circuit current (R=0) I=ε/r
- Magnetic induction vector B=Fmax/ℓ∙I
- Ampere Force Fa=IBℓsin α
- Lorentz force Fл=Bqυsin α
- Magnetic flux Ф=BSсos α Ф=LI
- Law of electromagnetic induction Ei=ΔФ/Δt
- EMF of induction in moving conductor Ei=Вℓ υ sinα
- EMF of self-induction Esi=-L∙ΔI/Δt
- The energy of the magnetic field of the coil Wm \u003d LI 2 / 2
- Oscillation period count. contour T=2π ∙√LC
- Inductive reactance X L =ωL=2πLν
- Capacitance Xc=1/ωC
- The current value of the current Id \u003d Imax / √2,
- RMS voltage Ud=Umax/√2
- Impedance Z=√(Xc-X L) 2 +R 2
Optics
- The law of refraction of light n 21 \u003d n 2 / n 1 \u003d υ 1 / υ 2
- Refractive index n 21 =sin α/sin γ
- Thin lens formula 1/F=1/d + 1/f
- Optical power of the lens D=1/F
- max interference: Δd=kλ,
- min interference: Δd=(2k+1)λ/2
- Differential grating d∙sin φ=k λ
The quantum physics
- Einstein's formula for the photoelectric effect hν=Aout+Ek, Ek=U ze
- Red border of the photoelectric effect ν to = Aout/h
- Photon momentum P=mc=h/ λ=E/s
Physics of the atomic nucleus