NationMaster - Encyclopedia: Longitudinal wave

Longitudinal waves are waves that have vibrations along or parallel to their direction of travel. They include waves in which the motion of the medium is in the same direction as the motion of the wave. Mechanical longitudinal waves have been also referred to as compressional waves or pressure waves. A wave is a disturbance that propagates through space or spacetime, transferring energy and momentum and sometimes angular momentum. ...

Plane pressure wave

Representation of the propagation of a longitudinal wave on a 2d grid (empirical shape)

1 Non-electromagnetic
- 1.1 Sound waves
- 1.2 Pressure waves
2 Electromagnetic
3 Media
4 Further reading
5 Patents
6 See Also
7 External articles
8 External links

Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

Non-electromagnetic

Examples of non-electromagnetic longitudinal waves include sound waves (alternation in pressure, particle displacement, or particle velocity propagated in an elastic material) and seismic P-waves (created by earthquakes and explosions). This article is about compression waves. ... Seismology (from the Greek seismos = earthquake and logos = word) is the scientific study of earthquakes and the movement of waves through the Earth. ... Plane P-wave Representation of the propagation of a P-wave on a 2d grid (empirical shape) One of the two types of elastic body waves (named because they travel through the body of the Earth) that are produced by earthquakes and recorded by seismometers. ... An earthquake is the result of a sudden release of stored energy in the Earths crust that creates seismic waves. ...

Sound waves

In the case of longitudinal harmonic sound waves, the frequency and wavelength can be described with the equation In acoustics and telecommunication, the harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency. ... FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. ... The wavelength is the distance between repeating units of a wave pattern. ...

$y(x,t) = y_0 sinBigg( omega left(t-frac{x}{c} right) Bigg)$

where:

y(x,t) is the displacement of particles from the stable position, in the direction of propagation of the wave;
x is the displacement from the source of the wave to the point under consideration;
t is the time elapsed;
$y 0$ is the amplitude of the oscillations,
c is the speed of the wave; and
ω is the angular frequency of the wave.

The quantity x/c is the time that the wave takes to travel the distance x. The term direction can be applied to various topics. ... In Newtonian mechanics, displacement is the vector that specifies the position of a point or a particle in reference to an origin or to a previous position. ... Amplitude is a nonnegative scalar measure of a waves magnitude of oscillation, that is, magnitude of the maximum disturbance in the medium during one wave cycle. ...

The (nonangular) frequency of the wave can be found using the formula

$f = frac{omega}{2 pi}$

where f is the frequency of the wave, usually measured in Hz. FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. ... MHZ redirects here. ...

For sound waves, the amplitude of the wave is the difference between the pressure of the undisturbed air and the maximum pressure caused by the wave. Amplitude is a nonnegative scalar measure of a waves magnitude of oscillation, that is, magnitude of the maximum disturbance in the medium during one wave cycle. ...

Sound's propagation speed depends on the type, temperature and pressure of the medium through which it propagates. Sound is a vibration that travels through an elastic medium as a wave. ...

Pressure waves

In an elastic medium with rigidity, a harmonic pressure wave oscillation has the form, Elasticity is a branch of physics which studies the properties of elastic materials. ... In mathematics, suppose C is a collection of mathematical objects (for instance sets or functions). ...

$y(x,t), = y_0 cos(k x - omega t +phi)$

where:

y₀ is the amplitude of displacement,
k is the wave number,
x is distance along the axis of propagation,
ω is angular frequency,
t is time, and
φ is phase difference.

The force acting to return the medium to its original position is provided by the medium's bulk modulus.^[1] Wavenumber in most physical sciences is a wave property inversely related to wavelength, having units of inverse length. ... A coordinate axis is one of a set of vectors that defines a coordinate system. ... Wave propagation refers to the ways waves travel through a medium (waveguide). ... It has been suggested that this article or section be merged into Angular velocity. ... A pocket watch, a device used to tell time Look up time in Wiktionary, the free dictionary. ... This article is about a portion of a periodic process. ... In physics, force is anything that can cause a massive body to accelerate. ... The bulk modulus (K) of a substance essentially measures the substances resistance to uniform compression. ...

Electromagnetic

Maxwell's equations lead to the prediction of electromagnetic waves in a vacuum, which are transverse (in that the electric fields and magnetic fields vary perpendicularly to the direction of propagation).^[2] However, in a plasma or a confined space, there can exist waves which are either longitudinal or transverse, or a mixture of both. ^[2]^[3] In plasma waves, there exists some examples and these plasma waves can occur in the situation of force-free magnetic fields. Maxwells equations are the set of four equations, attributed to James Clerk Maxwell (written by Oliver Heaviside), that describe the behavior of both the electric and magnetic fields, as well as their interactions with matter. ... A light wave is an example of a transverse wave. ... 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. ... Magnetic field lines shown by iron filings In physics, a magnetic field is a solenoidal vector field in the space surrounding moving electric charges and magnetic dipoles, such as those in electric currents and magnets. ... A plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation. ... A plasma is a quasineutral, electrically conductive fluid. ... A force-free magnetic field is a type of field which arise as a special case from the magnetostatic equation in plasmas. ...

In the early development of electromagnetism, there was some controversy, in that Helmholtz theory lead to the prediction of longitudinal waves. Oliver Heaviside examined this problem as there was no evidence suggesting that longitudinal electromagnetic waves existed in a vacuum. After Heaviside's attempts to generalize Maxwell's equations, Heaviside came to the conclusion that electromagnetic waves were not to be found as longitudinal waves in "free space" or homogeneous media.^[4] But, it should be stated, that longitudinal waves can exist along the interface between differing media (such as the various layers of the Earth's atmosphere and the surface of the Earth or as in the Schumann resonance). Oliver Heaviside (May 18, 1850 â€“ February 3, 1925) was a self-taught English electrical engineer, mathematician, and physicist who adapted complex numbers to the study of electrical circuits, developed techniques for applying Laplace transforms to the solution of differential equations, reformulated Maxwells field equations in terms of electric and... Look up Vacuum in Wiktionary, the free dictionary. ... In physics, free space is a concept of electromagnetic theory, corresponding roughly to the vacuum, the baseline state of the electromagnetic field, or the replacement for the electromagnetic aether. ... Layers of Atmosphereâ€”not to scale (NOAA) [1] Earths atmosphere is a layer of gases surrounding the planet Earth and retained by the Earths gravity. ... This article is about Earth as a planet. ... The Schumann resonance is a set of spectrum peaks in the extremely low frequency (ELF) portion of the Earths electromagnetic field spectrum. ...

Maxwell's equations do lead to the appearance of longitudinal waves under some circumstances in either plasma waves or guided waves. Basically distinct from the "free-space" waves, such as those studied by Hertz in his UHF experiments, are Zenneck waves. ^[5] The longitudinal mode of a resonant cavity is a particular standing wave pattern formed by waves confined in a cavity. The longitudinal modes correspond to the wavelengths of the wave which are reinforced by constructive interference after many reflections from the cavity's reflecting surfaces. A plasma is a quasineutral, electrically conductive fluid. ... In physics, a surface wave is a wave that is guided along the interface between two different media for a mechanical wave, or by a refractive index gradient for an electromagnetic wave. ... In physics, a surface wave is a wave that is guided along the interface between two different media for a mechanical wave, or by a refractive index gradient for an electromagnetic wave. ... The first six longitudinal modes of a plane-parallel cavity. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... A standing wave, also known as a stationary wave, is a wave that remains in a constant position. ... Interference of two circular waves - Wavelength (decreasing bottom to top) and Wave centers distance (increasing to the right). ...

Media

Video of a longitudinal wave ( file info) — Watch in browser
- Video of a longitudinal wave (166KB, Ogg/Theora format).
Problems seeing the videos? See media help.

Image File history File links Longitudinalwave. ... A kilobyte (derived from the SI prefix kilo-, meaning 1000) is a unit of information or computer storage equal to the decimal 1024 bytes (2 to the 10th power, or 1,024 bytes based in the binary system). ... Ogg is an open standard for a free container format for digital multimedia, unrestricted by software patents and designed for efficient streaming and manipulation. ... Theora is a video codec being developed by the Xiph. ...

Patents

U.S. Patent 2,226,688
U.S. Patent 3,488,602
U.S. Patent 3,515,911
U.S. Patent 3,518,780
U.S. Patent 4,242,742
U.S. Patent 4,481,822
U.S. Patent 4,702,110
U.S. Patent 5,168,234
U.S. Patent 5,760,522
U.S. Patent 6,439,034
U.S. Patent 6,535,665
U.S. Patent 6,600,391
U.S. Patent 6,611,412
U.S. Patent 6,806,620

External articles

Russell, Dan, "Longitudinal and Transverse Wave Motion". Acoustics Animations, Kettering University Applied Physics.

Longitudinal Waves, with animations "The Physics Classroom"

External links

An interactive simulation of longitudinal travelling wave
Wave types explained using high speed film and animations

Categories: Wave mechanics | Waves

Results from FactBites:

Longitudinal wave - Wikipedia, the free encyclopedia (819 words)
	Longitudinal waves, also referred to as compressional waves or pressure waves, are waves that have vibrations along or parallel to their direction of travel.
	For sound waves, the amplitude of the wave is the difference between the pressure of the undisturbed air and the maximum pressure caused by the wave.
	Ion acoustic wave : longitudinal oscillation of the ions (and the electrons) in an unmagnetized plasma or in a magnetized plasma parallel to the magnetic field.

More results at FactBites »

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