In physics, there are

equation In mathematics, an equation is a formula that expresses the equality of two expressions, by connecting them with the equals sign . The word ''equation'' and its cognates in other languages may have subtly different meanings; for example, in ...

s in every field to relate physical quantities to each other and perform calculations. Entire handbooks of equations can only summarize most of the full subject, else are highly specialized within a certain field.

Physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

is derived of formulae only.

General scope

* Variables commonly used in physics *

Continuity equation A continuity equation or transport equation is an equation that describes the transport of some quantity. It is particularly simple and powerful when applied to a conserved quantity, but it can be generalized to apply to any extensive quantity. S ...

Constitutive equation In physics and engineering, a constitutive equation or constitutive relation is a relation between two physical quantities (especially kinetic quantities as related to kinematic quantities) that is specific to a material or substance, and approx ...

Defining equation (physics) In physics, defining equations are equations that define new quantities in terms of base quantities. This article uses the current SI system of units, not natural or characteristic units. Description of units and physical quantities Physical q ...

Specific scope

Defining equation (physical chemistry) In physical chemistry, there are numerous quantities associated with chemical compounds and reactions; notably in terms of ''amounts'' of substance, ''activity'' or ''concentration'' of a substance, and the ''rate'' of reaction. This article uses ...

List of equations in classical mechanics Classical mechanics is the branch of physics used to describe the motion of macroscopic objects. It is the most familiar of the theories of physics. The concepts it covers, such as mass, acceleration, and force, are commonly used and known. The sub ...

Table of thermodynamic equations This article is a summary of common equations and quantities in thermodynamics (see thermodynamic equations for more elaboration). Definitions Many of the definitions below are also used in the thermodynamics of chemical reactions. General ...

List of equations in wave theory This article summarizes equations in the theory of waves. Definitions General fundamental quantities A wave can be longitudinal where the oscillations are parallel (or antiparallel) to the propagation direction, or transverse where the oscill ...

List of relativistic equations Following is a list of the frequently occurring equations in the theory of special relativity. Postulates of Special Relativity To derive the equations of special relativity, one must start with two other #The laws of physics are invariant ...

List of equations in fluid mechanics This article summarizes equations in the theory of fluid mechanics. Definitions Here \mathbf \,\! is a unit vector in the direction of the flow/current/flux. Equations See also * Defining equation (physical chemistry) *List of electro ...

List of electromagnetism equations This article summarizes equations in the theory of electromagnetism. Definitions Here subscripts ''e'' and ''m'' are used to differ between electric and magnetic charges. The definitions for monopoles are of theoretical interest, although rea ...

List of equations in gravitation This article summarizes equations in the theory of gravitation. Definitions Gravitational mass and inertia A common misconception occurs between centre of mass and centre of gravity. They are defined in similar ways but are not exactly the ...

* List of photonics equations *

List of equations in quantum mechanics This article summarizes equations in the theory of quantum mechanics. Wavefunctions A fundamental physical constant occurring in quantum mechanics is the Planck constant, ''h''. A common abbreviation is , also known as the ''reduced Planck co ...

List of equations in nuclear and particle physics This article summarizes equations in the theory of nuclear physics and particle physics. Definitions Equations Nuclear structure Nuclear decay Nuclear scattering theory The following apply for the nuclear reaction: :''a'' + ''b'' � ...

Units and nomenclature

Physical constant A physical constant, sometimes fundamental physical constant or universal constant, is a physical quantity that is generally believed to be both universal in nature and have constant value in time. It is contrasted with a mathematical constant, ...

Physical quantity A physical quantity is a physical property of a material or system that can be quantified by measurement. A physical quantity can be expressed as a ''value'', which is the algebraic multiplication of a ' Numerical value ' and a ' Unit '. For examp ...

SI units The International System of Units, known by the international abbreviation SI in all languages and sometimes Pleonasm#Acronyms and initialisms, pleonastically as the SI system, is the modern form of the metric system and the world's most wid ...

SI derived unit SI derived units are units of measurement derived from the seven base units specified by the International System of Units (SI). They can be expressed as a product (or ratio) of one or more of the base units, possibly scaled by an appropriate po ...

SI electromagnetism units See also * SI * Speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory o ...

List of common physics notations This is a list of common physical constants and variables, and their notations. Note that bold text indicates that the quantity is a vector. Latin characters Greek characters Other characters See also * List of letters used in mathemat ...

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