See scalar for an account of the broader concept also used in mathematics and computer science. In physics, a scalar is a simple physical quantity that does not depend on direction, and is therefore not changed by coordinate system rotations (in Newtonian mechanics), or by Lorentz transformations (in relativity). (Contrast to vector.) A scalar may be: Look up scalar in Wiktionary, the free dictionary. ...
A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ...
A physical quantity is either a quantity within physics that can be measured (e. ...
The shape of each panel of this road sign, and the broken lines at the ends, represents an arrow; a space-consuming central bar of the arrow sign is dispensed with. ...
In mathematics as applied to geometry, physics or engineering, a coordinate system is a system for assigning a tuple of numbers to each point in an n-dimensional space. ...
The Lorentz transformation (LT), named after its discoverer, the Dutch physicist and mathematician Hendrik Antoon Lorentz (1853-1928), forms the basis for the special theory of relativity, which has been introduced to remove contradictions between the theories of electromagnetism and classical mechanics. ...
In physics and in vector calculus, a spatial vector is a concept characterized by a magnitude, which is a scalar, and a direction (which can be defined in a 3-dimensional space by the Euler angles). ...
Examples The cow jumped over the moon!For example, the distance between two points in space is a scalar, as are the mass, charge, and kinetic energy of an object, or the temperature and electric potential at a point inside a medium. On the other hand, the electric field at a point is not a scalar in this sense, since to specify it one must give three real numbers that depend on the coordinate system chosen. The speed of an object is a scalar (e.g. 180 km/h), while its velocity is not (i.e. 180 km/h north). The gravitational force acting on a particle is not a scalar, but its magnitude is. Distance is a numerical description of how far apart objects are at any given moment in time. ...
For other uses, see Mass (disambiguation). ...
In physics, a charge may refer to one of many different quantities, such as the electric charge in electromagnetism or the color charge in quantum chromodynamics. ...
The cars of a roller coaster reach their maximum kinetic energy when at the bottom of their path. ...
For other uses, see Temperature (disambiguation). ...
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In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field. ...
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This article is about velocity in physics. ...
Gravity redirects here. ...
For other uses, see Force (disambiguation). ...
The magnitude of a mathematical object is its size: a property by which it can be larger or smaller than other objects of the same kind; in technical terms, an ordering of the class of objects to which it belongs. ...
Examples of scalar quantities in Newtonian mechanics:
A physical quantity is expressed as the product of a numerical value and a physical unit, not just a number. It does not depend on the unit distance (1 km is the same as 1000 m), although the number depends on the unit. Thus distance does not depend on the length of the base vectors of the coordinate system. Also, other changes of the coordinate system may affect the formula for computing the scalar (for example, the Euclidean formula for distance in terms of coordinates relies on the basis being orthonormal), but not the scalar itself. In this sense, physical distance deviates from the definition of metric in not being just a real number; however it satisfies all other properties. The same applies for other physical quantities which are not dimensionless. Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ...
Charge density is the amount of electric charge per unit volume. ...
For other uses, see Mass (disambiguation). ...
Density (symbol: Ï - Greek: rho) is a measure of mass per unit of volume. ...
This article does not cite any references or sources. ...
This article is about velocity in physics. ...
This article is about momentum in physics. ...
For other uses, see Temperature (disambiguation). ...
Energy density is the amount of energy stored in a given system or region of space per unit volume, or per unit mass, depending on the context. ...
Look up time in Wiktionary, the free dictionary. ...
This article is about pressure in the physical sciences. ...
For other uses, see: information entropy (in information theory) and entropy (disambiguation). ...
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Quantity is a kind of property which exists as magnitude or multitude. ...
For other uses, see Number (disambiguation). ...
The definition, agreement and practical use of units of measurement have played a crucial role in human endeavour from early ages up to this day. ...
In linear algebra, two vectors v and w are said to be orthonormal if they are both orthogonal (according to a given inner product) and normalized. ...
In mathematics a metric or distance function is a function which defines a distance between elements of a set. ...
Scalars in relativity theory In the theory of relativity, one considers changes of coordinate systems that trade space for time. As a consequence, several physical quantities that are scalars in "classical" (non-relativistic) physics need to be combined with other quantities and treated as four-dimensional vectors or tensors. For example, the charge density at a point in a medium, which is a scalar in classical physics, must be combined with the local current density (a 3-vector) to comprise a relativistic 4-vector. Similarly, energy density must be combined with momentum density and pressure into the stress-energy tensor. Two-dimensional analogy of space-time curvature described in General Relativity. ...
Charge density is the amount of electric charge per unit volume. ...
In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ...
Energy density is the amount of energy stored in a given system or region of space per unit volume, or per unit mass, depending on the context. ...
This article is about pressure in the physical sciences. ...
This article is in need of attention from an expert on the subject. ...
Examples of scalar quantities in relativity:
A related concept is a pseudoscalar, which is invariant under proper rotations but (like a pseudovector) flips sign under improper rotations. One example is the scalar triple product (see vector), and thus the signed volume. Another example is magnetic charge (as it is mathematically defined, regardless of whether it actually exists physically). Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ...
For other uses of this term, see Spacetime (disambiguation). ...
In relativity, proper time is time measured by a single clock between events that occur at the same place as the clock. ...
In physics, proper length is the length of an object or a contour as measured in the reference frame of the object itself in the context of special relativity. ...
The invariant mass or intrinsic mass or proper mass or just mass is a measurement or calculation of the mass of an object that is the same for all frames of reference. ...
In mathematics and physics, a pseudoscalar is a quantity that behaves more or less like a scalar, except that it transforms oddly under the action of a discrete group. ...
In geometry, an improper rotation is the combination of an ordinary rotation of three-dimensional Euclidean space, that keeps the origin fixed, with a coordinate inversion (a vector x goes to −x). ...
In physics and mathematics, a pseudovector (or axial vector) is a quantity that transforms like a vector under a proper rotation, but gains an additional sign flip under an improper rotation (a transformation that can be expressed as an inversion followed by a proper rotation). ...
In geometry, an improper rotation is the combination of an ordinary rotation of three-dimensional Euclidean space, that keeps the origin fixed, with a coordinate inversion (a vector x goes to −x). ...
In vector calculus, there are two ways of multiplying three vectors together, to make a triple product of vectors. ...
This article is about vectors that have a particular relation to the spatial coordinates. ...
In physics, magnetic monopole is a term describing a hypothetical particle that could be quickly clarified to a person familiar with magnets but not electromagnetic theory as a magnet with only one pole. In more accurate terms, it would have net magnetic charge. Interest in the concept stems from particle...
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