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19 Cards in this Set
- Front
- Back
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Metric System - G, M, K, c,m, u, n
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Giga: 9, Mega: 6, Kilo: 3, centi: -3, micro: -6, nano: -9
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Period and Frequency definitions and relationship
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Period: T time to complete one cycle
Frequency: F cycle per second Hz F= 1/T |
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Angular Frequency definition and equation
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equivalent of frequency in radians per second
w=2 pi frequency |
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Simple Harmonic Motion equation
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y(t)=ACos(wt+angle)
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Sound is what type of wave
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Mechanical (particles oscillate) longitudinal (parallel)
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Acoustic Variables Measured by Amplitude
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Pressure - F/A pascals, torrs, mmHg
Density - m/v g/L, kg/cc Temperature - Celsius, Fahrenheit Distance - displacement |
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Characterisitics of Sound wave
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frequency, period, velocity, wavelength, power, intensity, amplitude
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Frequencies of Sound, infra, ultra, audible, diagnostic, medical
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<20Hz Infra, 20-20,000 Audible, >20kHz ultra
2-20 MHz Diagnostic .5-40 MHz Medical |
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As frequency increases what happens to attenuation and depth of penetration
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F inc, attenuation inc, depth of penetration decreases
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equation for wavelength with velocity and frequency
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lamba = v/f. increase frequency decrease wavelength
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Wavelength depends on....velocity depends on...frequency depends on...
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Wavelength - propagation speed in medium
Velocity - medium characteristics Frequency - crystal thickness and velocity |
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Characteristics of the Medium first equation
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v = stiffness of medium / inertia
Stiffness = incompressible and inelastic Inertia = density |
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4 Characterisitics that impact velocity of the medium
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1) Compressibilty - decrease volume due to pressure
2) Elasticity - return to orginal shape after distention 3) Density - mass per area 4) Bulk Modulus = - stress/strain |
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Bulk Modulus
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B=-stress/strain
Stress = applied force per area (pressure) Strain = compressibility |
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Propagation Speed equation #2
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v= square root of bulk modulus over density
Compressibility most important factor(inverse of bulk modulus) |
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Comparative Sound Velocity
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Air < Lung < Fat < Soft Tissue < Muscle < Bone
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Power definition and equations, units
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amount of work per unit of time, rate of which energy is transferred, heat.
P=W/T Watts |
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Intensity definition, equation, units
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loudness, concentration of energy in sound beam
I=Power/Area, Units Watt/cm squared |
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Intensity Power and Amplitude relationship and examples
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I proportional to Power proportional to Amplitude 2
Increase A by 2 = Increase I/P by 4 Decrease I by 2 = Decrease P by 2 and A by square root 2 |
