47 terms

# Unit 12: Physics.

###### PLAY
What are multiple echoes called ?
reverberations
"Dead spots" in an auditorium are the results of
destructive interference
Twice the freq of a musical note
octave
The pitch of a wind instrument depends on the ____ of the air column
length
the fundamental mode plus overtones is
harmonics
the freq of the ___ overtone of a 100 Hz note is 600 Hz
fifth
Mixture of sound freq w/ a pattern is
Music
the ___ mode determines the pitch of a musical sound
fundamental
whole number multiples of the fundamental mode
overtones
This is a pulsing sound as the result of interference of sound waves of slightly different frequencies
beats
the first overtone of a note is the _____
second
random mix of many sound frequencies
noise
sound ___ depends on the number and relative intensity of harmonics
quality
the bending downward of sound waves as they move into a layer of cool air is an example of
refraction
decreasing the ___ of a vibrating sting lowers the pitch
tension
when tuning fork matches the freq of a piano string ___ occurs
resonance
the pitch of a percussion instrument depends on
mass
Speed of sound in air equation ?
v = 331 m/s + (0.6 m/s/c)(t)
Echo equation?
V=2d/t
Velocity equation?
V=FY
Intensity equation?
I=P/A
Sound waves are ______, ______ waves
mechanical , longitudinal
Sound waves consist of ____ and ____ rather than crests and troughs
compressions and rarefractions
The velocity of a sound wave depends on the ____
medium
The upper limit of sound intensity is called the threshold of ____
pain
THe lower limit of sound intensity is called the threshold of ____
hearing which is 1.0 X 10^-12 w/m^2 at 1000 Hz
Compared to speed of light, sound is much ____ and compared to energy of light, sound is much _____
slower, less
sound waves cannot travel thru a ____
vacuum
Of the 3 phases of matter, sound travels fastest in
solids
Sound travels slowest in ___
gases
sound travels ___ in hot air then cold air
faster
The ____ range of freq for the avg human is ___
audible, 20-20,000
Sounds of higher freq are called
ultrasonic
sounds of lower freq are called
infrasonic
the ____ is the dimensionless unit for B which is relative ____
dB, intensity
sound intensity is ____ divided by ___ and the best measure of loudness
power, areas
sound intensity _____ as the distance from the source increases
decreases
change in pitch of a sound as the source and observer move towards or away from ech other is __
doppler effect, used for tracking storms and car speed direction
____ occurs when an outside force matches the ___ freq of an object, result is dramatic increase in ___ of waves
resonance, natural, amplitude
____ can be heard when two tuning forks of diff freq are sounded together. this results from constructive and destructive interference of the two sound waves produced
Beats
echoes are ___ sound waves, and ___ are multiple echoes
reflected, reverberation
___ - one is the speed of sound
Mach
A ____ plane travels faster than sound
supersonic
Trailing behind a supersonic plane is a ____ shaped region of compressed air producing a ____ ______
cone, sonic boom
To raise pitch of a wind instrument you ___
decrease size of air column
To raise pitch of string instrument you ___
increase tension, increase density, decreased length of string, and diameter decreases
To raise pitch of a percussion instrument you ___
decrease mass of the object