Cartesian coordinatesMain articles: Standard basis and Versor (physics)Unit vectors may be used to represent the axes of a Cartesian coordinate system. For instance, the unit vectors codirectional wit ...
The Planck constant (denoted h, also called Planck's constant) is a physical constant that is the quantum of action in quantum The Planck constant has dimensions of physical action; these are the same ...
The Middle English word ure first appears in the 13th century, as a loanword from Old French ure, ore, from Latin hōra. Hora, in turn, derives from Greek ?ρα ("season, time of day, hour"). In term ...
English high is derived from Old English hēah, ultimately from Proto-Germanic *xauxa-z, from a PIE base *keuk-. The derived noun height, also the obsolete forms heighth and highth, is from Old Englis ...
The International System of Units (SI) unit symbol for the gram is "g" following the numeric value with a space, as in "640 g". It is not "gr" (which is the symbol for grains):C-19, "gm" (easily mista ...
For cyclical processes, such as rotation, oscillations, or waves, frequency is defined as a number of cycles per unit time. In physics and engineering disciplines, such as optics, acoustics, and radio ...
The first references to the constant were published in 1618 in the table of an appendix of a work on logarithms by John Napier. However, this did not contain the constant itself, but simply a list of ...
Imprecise calculations with infinitesimals were widely replaced with the rigorous (ε, δ)-definition of limit starting in the 1870s. Meanwhile, calculations with infinitesimals persisted and often le ...
Main article: History of calculusModern calculus was developed in 17th century Europe by Isaac Newton and Gottfried Wilhelm Leibniz, but elements of it have appeared in ancient Greece, China, medieval ...
The reflectance or reflectivity is the square of the magnitude of the reflection coefficient. The reflection coefficient can be expressed as a complex number as determined by the Fresnel equations for ...
General physical considerations The medium in which a sound wave is travelling does not always respond adiabatically, and as a result the speed of sound can vary with frequency.The limitations of the ...
The speed of sound was first accurately calculated by the Reverend William Derham, Rector of Upminster, improving on Newton's estimates. Derham used a telescope from the tower of the church of St Laur ...
Mathematically, instantaneous acceleration—acceleration over an infinitesimal interval of time—is the rate of change of velocity over time:\mathbf{a} = \lim_{{\Delta t}\to 0} \frac{\Delta \mathbf{v} ...
where S is the action functional.The partition function in quantum field theory is a special case of the mathematical partition function, and is related to the statistical partition function in statis ...
As a beginning assumption, assume that a thermodynamically large system is in thermal contact with the environment, with a temperature T, and both the volume of the system and the number of constituen ...
