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Speech & Hearing Science Exam 1
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Gravity
Terms in this set (97)
Sound 1
The transfer of acoustic energy through an elastic medium
Commonly used medium
Atmospheric air
Sound 2
A propagation pattern of pressure or changes in density in an elastic medium
Qualities of a medium
Elasticity & density
Amount of PSI pushing down on us/Atmospheric pressure
15 psi
15 psi equals
1 million Dynes
Density
The amount of mass per unit volume
Elasticity
The tendency of a volume of mass to return to its original volume following compression
Amount of pressure change needed to make a sound
+/- .0002 Dynes/cm squared
Requirements for sound to occur
Source & elastic medium
Source
Vibrating object, impulse, or other means of causing the initial condensation or rarefaction
Properties of a mechanical system
Resistance, mass & stiffness
Components of the restoring force
Velocity, acceleration & displacement
The elastic property of the system
Restoring force
Mass x Velocity=
Momentum
Hook's Law
States that the restoring force is proportional to the magnitude of displacement
Sine wave
Demonstration of some rhythmic activity over time
Acceleration=
Velocity change
Velocity is greatest when...
It travels past the neutral position
Momentum is greatest when...
The elastic force is at the neutral position
The more the displacement...
The greater the restoring force
Two properties that are very intimately related
Pressure & velocity
When ______ & ______ are at their maximum, _____ is at its minimum
Displacement, Deceleration, Velocity
When _____ is at its maximum, ______ & _____ are at their minimum
Velocity, Displacement, Deceleration
Longitudinal waves
Sound waves
Transverse waves
Particles of the medium move at 90 degrees to the direction of the wavefront
Longitudinal waves
Particles of the medium move in the same direction as the wavefront
Potential energy
Stored energy possessed by a system as a result of the relative positions of the components of that system
Kinetic energy
Energy possessed by an object resulting from the motion of that object
Simple harmonic motion
Motion that changes in both magnitude and direction over time
Simple harmonic motion
A.K.A. sinusoidal motion or projected uniform circular motion
Uniform circular motion
Moving around the circumference of a circle at a constant speed or constant number of degrees per second
2 Hertz
If you go around the circle twice in one second
1 Hertz
If you go around the circle once in one second
Standard time value
1 second
Phase angle
A reference point on a sine wave or circle at a particular point in time.
______ is constant but _____ can vary
Phase, time
Dimensions of sound waves
Amplitude, frequency, period, phase & wavelength
Concept that most often involves force
Amplitude
Dyne
The force required to accelerate a mass of 1 gram from a velocity of 0 cm/sec to a velocity of 1 cm/sec in one second
Dyne
Used in all measures of amplitude when talking about sound
Instantaneous Amplitude
The amount of displacement in the medium at a particular reference point in time
Peak Amplitude
The distance from the point of rest to the point of maximum displacement
Peak-to-Peak Amplitude
The distance from the point of maximum positive displacement to the maximum negative displacement
Root Mean Square Amplitude
The square root of all the displacement deviation values squared
RMS equals
.707 x peak amplitude
RMS on a sine wave equals
45 degrees
Frequency
The rate in cycles per second at which a vibratory motion repeats itself
Frequency equals
1/Period
Inversely proportional to length and mass
Frequency
Directly proportional to stiffness/tension
Frequency
Phase relation between mass and stiffness
180 degrees out of phase
Period
The time that it takes to complete one cycle of motion
Period equals
1/Frequency
_____&_____ are reciprocals
Frequency and period
Phase
The fraction of the period that has elapsed since the vibratory disturbance passed some reference point
Cosine
Starting phase of 90 degrees
Sine
Starting phase of 0 degrees
Antinode
Areas in which the sound pressure is higher
Node
Areas in which the sound pressure is lower
Complete destructive interference
180 degrees out of phase/cancellation
Complete constructive interference
Two waveforms exactly in phase with one another/summation
Beats
Caused by partial destructive/constructive interference
Wavelength
The distance a sound travels in one period
Speed of sound in air
340 Meters/1100 Feet per second
Constant speed of sound equals
Frequency x wavelength
Wavelength equals
Constant/Frequency
Seconds or Milliseconds
Label for period
Hertz
Label for frequency
Ft/Sec or M/Sec
Label for Constant Speed
Feet
Label for wavelength
Volts
Label for RMS
Add
When multiplying two numbers with exponents you
Subtract
When dividing two numbers with exponents you
Add
When multiplying two logs you
Subtract
When dividing two logs you
Work equals
Force x Distance
Work
Is done when a force acts (does something) through a distance
Erg
The basic unit of work
Erg
The amount of work done by one dyne acting through a distance of 1 cm
Watt
The basic unit of power
Power
Work done in a given unit of time
Power equals
Work/Time
Sound Intensity/Power
The flow of sound energy, as measured in terms of power through a given area
Pressure equals
Force/Area
Erg
Label for work
Watt/Microwatt per centimeter squared
Label for power
10 to the -16
Reference value for intensity
0.0002 dynes/cm
Reference value for pressure
Pressure
Force acting over a given area
Dynes/cm squared
Label for pressure
Level of Pain
2000 dynes or 120 dB
Threshold of hearing
.0002 dynes or 0 dB
Each Bel equals
10 dB (10:1 ratio)
Logarithm
The power to which a given number is raised to give another number
Decibel formula for intensity
10Log(I/I)
Decibel formula for pressure
20Log(P/P)
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