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Definition
The time required for the completion of one cycle of a periodic motion. |
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The number of cycles per second. |
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Any back and forth movement between two states. |
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Mechanical oscillation with elasticity acting as the restoring force. |
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The motion of an object in which changes in displacement, velocity, and acceleration are sinusoidal functions of time. |
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Definition
A motion that repeats itself in regular intervals until stopped by an external force. |
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A motion in thich the acceleration of the object is directly proportional but opposite in direction to the displacement of the object from its equilibrium position. |
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Definition
A function representing changes of any physical quantity as a function of time. |
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Definition
Process of conveying energy through space via a wave motion. |
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Transfer of mechanic energy from one molecule to another. |
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A substance that occupies a space; can be solid, fluid, or gas. |
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Any event that causes a change in medium at a specific location. |
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Waves in which the particles of the medium are displaced in the same direction as the wave propagation. |
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Definition
Bunching of particles causing increased density. |
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Definition
Spreading of particles causing decreased density. |
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Particles of a medium are displaced in a directon that is perpendicular to the direction of wave propagation. |
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Definition
Complex waves created when a mechanic disturbance arrives at a border between two media having different densities; combination of transverse and longitudinal waves. |
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Definition
A disturbance in an elastic medium that propogated through the medium as a longitudinal wave; a stimulus that causes an auditory sensation. |
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Definition
The rate at which energy propagates through a medium. |
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Definition
The distance in space between two adjacent identical points of a propagating wave. |
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Definition
The energy transferred from the vibrating source to the medium and propagates through the medium in the form of density changes. |
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Definition
Very low frequency sounds that cannot be heard (below 20Hz). |
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Definition
Very high frquency sounds that cannot be heard (above 20kHz). |
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Definition
Tone with only one frequency. |
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Tone with more than one frequency. |
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Sounds where maginitude at different points in time can be predicted. |
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Definition
Sounds where future behavior cannot be predicted; random. |
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Random sound with acoustic properties that do not vary much over time. |
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Definition
Noise content and intensity change randomly and noise properties cannot be predicted over time. |
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The absolute difference between that phases of two waveforms with neither considered as a point of reference; maximum difference = 180 degrees. |
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Definition
The relationship between the phase of one waveform and another where one is considered the point of reference. |
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Definition
When two waveforms have the same frequency and phase. |
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Definition
When two waveforms have the same frequency, but different phases. |
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Definition
The magnitude of a waveform observed at any given time. |
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Definition
The maximum/peak magnitude of a waveform. |
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Definition
The whole range of magnitude changes within one period. |
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Definition
The average value of the magnitude calculated across the whole period of a waveform. |
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Root mean square (RMS) magnitude |
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Definition
Constant magnitude derived from the root of the mean of the squares of the instantaneous magnitudes calculated across the waveform's period. |
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Definition
A mechanical property of an elastic object that describes its opposition to the change of its dimensions by an external force. |
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Definition
A system that does not exchange its energy with the environment; no loss of energy. |
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Definition
A system that loses part of its energy to the surrounding environment due to the effect of friction. |
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Definition
The back and forth vibration of a system in which no additional energy is added once it is set into motion. |
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Definition
The natural frequency at which a system will vibrate when left alone. |
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Definition
A vibration in which a system is forced to vibrate by an applied force. |
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Definition
The force that opposes the relative motion of two bodies in contact and causes the conversion of system energy into heat. |
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Definition
The loss of energy in a vibrating system due to dissipation to the surrounding environment; causes a gradual decrease in amplitude. |
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Very little system friction. |
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Definition
Indicates the most rapid response to a sudden change of force without overshooting the equilibrium. |
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A lot of system friction. |
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Definition
Specifies time in seconds after which the amplitude of vibration decreases by ~63%. |
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Definition
The overall duration needed to change from 10% to 90% of a waveform's peak. |
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The time period during which a waveform has a relatively constant amplitude. |
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Definition
The time needed for a waveform to change from 90% to 10% of its peak value. |
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Definition
The dependence of the amplitude of vibrationof the frequency of the driving force. |
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Definition
The sum of two or more simple vibrations. |
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Definition
Any complex waveform is the sum of various sinusoids of varying amplitude, frequency, and phase. |
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Definition
A vibration without a repeating pattern. |
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Definition
Vibratory motion in which an object returns to the same point in space at equal periods of time during the motion. |
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Definition
The process of combining several sine waves into a complex waveform. |
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Definition
Whole-number multiple frequency components of a complex waveform. |
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Definition
The largest common factor from a group of harmonically related components is equal to its fundamental. |
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Definition
When the GCF of a set of harmonics is not present in the waveform. |
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The concept that a periodic waveform repeats itself for an infinite amount of time. |
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Definition
Random sequence of events resulting from the combination of a large number of unrelated frequencies. |
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Definition
A brief, single event that ceases to exist after a very short time. |
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Complex inharmonic motion |
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Definition
The sum of a finite number of frequencies that does not repeat its pattern within an observed period of time. |
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Definition
The process of taking complex waveforms apart into individual components. |
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Definition
Representation of a phenomenon as a function of time. |
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Definition
A graphical representation of a complex waveform showing the waveform energy (amplitude) of the individual components (y-axis) arranged in order of frequency (x-axis). |
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Definition
Representation of a phenomenon as a function of frequency. |
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Definition
A spectrum that consists of one or more separate vertical lines. |
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Amplitude/frequency spectrum |
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Definition
Displays the amplitude of various vector quantities associated with the components (velocity, force, displacement, etc.). |
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Definition
A spectrum in which the energy of spread across a wide range of frequencies rather than at discrete sinusoidal components. |
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Definition
Displays the power (energy) of the components. |
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Definition
The points of the vibrating system at which displacement remains zero. |
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Definition
The points at which the vibration magnitude is greatest. |
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Definition
The specific vibration pattern of a vibrating system associated with each rosonance frequency of the system. |
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Definition
The opposition to the flow of energy through a system and any change in its state. |
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Definition
The opposition of a system to movement caused by friction. |
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Definition
The opposition of a system to a change in its state by the system's ability to store energy and prevent its transfer to or from another system. |
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Definition
The ability of the mass to store energy. |
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Definition
The ability of the stiffnes to store energy. |
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Definition
The wase with which energy travels through a friction element in the system. |
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Definition
The ease with which energy travels through a stiffness element in the system. |
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Definition
The ease with which energy flows through a mass. |
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Definition
The ease with which energy travels through s spring element. |
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Definition
The ease with which a system can vibrate due to an applied force. |
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Term
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Definition
The practice of making the impedance of the source of power equal to the impedance of the load to transfer as much energy as possible from the source to the load. |
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Term
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Definition
If mass reactance is greater than stiffness reactance. |
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Term
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Definition
If stiffness reactance is greater than mass reactance. |
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Term
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Definition
Sound wave will lose energy due to absorption by the medium and surrounding boundaries. |
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Term
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Definition
The ability of a medium and its boundaries to absorb the energy of sound waves. |
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Term
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Definition
The bouncing of sound waves off of a boundary. |
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Term
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Definition
The bending of sound waves due to a change in the speed of sound propagation; caused by sound waves entering a different medium or changes in temperature. |
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Term
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Definition
The original, incoming sound wave. |
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Term
Total internal reflection |
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Definition
A situation where 100% of the sound energy reaching a boundary is reflected back into the original medium. |
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Term
Critical angle of incidence |
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Definition
The smallest angle of incidence for which total internal reflection can occur. |
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Definition
The effect of bending sound waves away from the ground when warmer air is nearer to the ground and colder air is above it. |
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Definition
When colder air is closer to the ground and warmer air is above it, waves bend toward the ground. |
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Definition
The time needed for a sound pressure to decrease 1000 times after the sound source ceases its operation. |
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Definition
The reflected sound energy within an enclosed space. |
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Definition
Closed spaces with highly reflective surfaces that do not absorb sound waves. |
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Definition
Rooms with very soft walls, ceilings, etc. that absorb most of the sound energy. |
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Definition
An area behind a boundary that the direct sound waves does not enter. |
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Definition
The phenomenon of sound waves bending around objects and through openings in barriers. |
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Term
Constructive interference |
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Definition
An increase in amplitude of sound waves when two or more sund waves travel through the same space and are in-phase. |
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Term
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Definition
A decrease in the amplitude of at least one sound wave when two sound waves travel through the same space and are out-of-phase. |
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Term
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Definition
Slow, periodic amplitude fluctuations caused when two sine waves that are very close to each other in frequency interfere with one another. |
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Definition
A space containing sound waves. |
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Definition
The resulting vibrations in a sound pressure near the sound source; characterized by large and nonuniform maxima and minima in acoustic pressure that gradually disappear into a uniform signal with increasing distance from the source. |
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Definition
The region of uniformly decreasing sound pressure (1/r) observed far away from the sound source. |
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Definition
Sound field created by a sound source in an unbound space. |
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Definition
Sound field in which sound propagation is not affected by objects or boundaries. |
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Definition
Sound field where sound energy reflected from space boundaries dominates the sound energy propagating from the sound source. |
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Definition
And area filled with sound energy from random reflections coming from all directions and in which all SPLs are the same. |
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Definition
The distance from the sound source where the intensity of both fields is about equal. |
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Definition
The ratio of intensity of a signal to the intensity of a noise. |
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Definition
Additional length added to a mass of a vibrating system to determine the resonance frequency of a tube with an open end. |
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