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In classical mechanics, a kinematic pair is a connection between two physical objects that imposes constraints on their relative movement ().German engineer Franz Reuleaux introduced the kinematic pair as a new approach to the study of machines [1] that provided an advance over the notion of elements consisting of simple machines.
This does not mean that a vibrational mode which is not Raman active must be IR active: in fact, it is still possible that a mode of a particular symmetry is neither Raman nor IR active. Such spectroscopically "silent" or "inactive" modes exist in molecules such as ethylene (C 2 H 4), benzene (C 6 H 6) and the tetrachloroplatinate ion (PtCl 4 2 ...
In logic, the law of non-contradiction (LNC) (also known as the law of contradiction, principle of non-contradiction (PNC), or the principle of contradiction) states that contradictory propositions cannot both be true in the same sense at the same time, e. g. the two propositions "the house is white" and "the house is not white" are mutually exclusive.
In logic, two propositions and are mutually exclusive if it is not logically possible for them to be true at the same time; that is, () is a tautology. To say that more than two propositions are mutually exclusive, depending on the context, means either 1. "() () is a tautology" (it is not logically possible for more than one proposition to be true) or 2. "() is a tautology" (it is not ...
In physics, a number of noted theories of the motion of objects have developed. Among the best known are: Classical mechanics. Newton's laws of motion; Euler's laws of motion; Cauchy's equations of motion; Kepler's laws of planetary motion ; General relativity; Special relativity; Quantum mechanics
Galilean invariance or Galilean relativity states that the laws of motion are the same in all inertial frames of reference. Galileo Galilei first described this principle in 1632 in his Dialogue Concerning the Two Chief World Systems using the example of a ship travelling at constant velocity, without rocking, on a smooth sea; any observer below the deck would not be able to tell whether the ...
The most popular in the general physics literature and historically first of these is the Wigner quasiprobability distribution, [4] which is related to symmetric operator ordering. In quantum optics specifically, often the operators of interest, especially the particle number operator , is naturally expressed in normal order .
Observable quantities corresponding to mutually exclusive laboratory arrangements cannot be predicted together, but the consideration of multiple such mutually exclusive experiments is necessary to characterize a system. Hans Primas and Roland Omnès give a more detailed breakdown that, in addition to the above, includes the following: [5]: 85