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Unit 7 – Waves and Sound
Lesson4:DecibelsandDopplerEffect
SuggestedReadings SoundIntensityandDecibels:• PhysicsClassroom.com->Tutorial->SoundWavesandMusic->
Lesson2(secFonbonly)
DopplerEffect:• PhysicsClassroom.com->Tutorial->Waves->Lesson3(secFond
only)• PhysicsClassroom.com->Tutorial->SoundWavesandMusic->
Lesson3(secFonbonly)Both:• HoltPhysicstextbook->Chapter12(Sound)->Pg.412-417
SoundIntensity
InordertoquanFfythe“loudness”ofasound,mustfirstthinkaboutthesound’sintensity
SoundIntensity
InordertoquanFfythe“loudness”ofasound,mustfirstthinkaboutthesound’sintensity
IntensityisameasureoftherateatwhichenergyisbeingtransmiXedoveragivenarea
SoundIntensity
InordertoquanFfythe“loudness”ofasound,mustfirstthinkaboutthesound’sintensity
Remember,theword“rate”indicateshowmuchofsomething(energyhere)istransmiXedoverFme.
IntensityisameasureoftherateatwhichenergyisbeingtransmiXedoveragivenarea
SoundIntensity
InordertoquanFfythe“loudness”ofasound,mustfirstthinkaboutthesound’sintensity
Remember,theword“rate”indicateshowmuchofsomething(energyhere)istransmiXedoverFme.So“intensity”israteofenergytransmissionoversomeareainspace.
IntensityisameasureoftherateatwhichenergyisbeingtransmiXedoveragivenarea
SoundIntensity
EquaFonforintensity:
I =
Energytime
Area
SoundIntensity
EquaFonforintensity:
I =
Energytime
AreaRateofenergytransmission
SoundIntensity
EquaFonforintensity:
I =
Energytime
AreaAreaofsurfacetheenergyistransmiXedthrough
SoundIntensity
EquaFonforintensity:
I =
Energytime
Area=
Power
Area
SoundIntensity
EquaFonforintensity:UnitsofPower:WaXs(Joules/second)UnitsofArea:meters2=>SoUnitsofIntensity:WaXs/m2
I =Energytime
Area=
Power
Area
SoundIntensity
EquaFonforintensity:Asitstands,thisequaFonisnotreallyusefulforourpurposes.Forexample,howdowecalculatearea,especiallyifwedon’thaveanactualsurfaceinmind?
I =Energytime
Area=
Power
Area
SoundIntensity–PointSourceWecanstarttomakesomesimplificaFonstomakethingseasier:First,let’sdefinea“pointsource”
SoundIntensity–PointSourceWecanstarttomakesomesimplificaFonstomakethingseasier:First,let’sdefinea“pointsource”WemaketheassumpFonthatsoundisemiXedfromasinglepointinspace.
SoundIntensity–PointSourceWecanstarttomakesomesimplificaFonstomakethingseasier:First,let’sdefinea“pointsource”WemaketheassumpFonthatsoundisemiXedfromasinglepointinspace.
=>ThisdrasFcallysimplifiesthings,becausenowwedon’thavetothinkabout
complicatedsoundemission
SoundIntensity–PointSourcePointSource:Sothesourceiswhateverisemibngthesound,andweassumethatitcomesfromasinglepointinspace.
SoundIntensity–PointSourcePointSource:Sothesourceiswhateverisemibngthesound,andweassumethatitcomesfromasinglepointinspace.
=>NOTE:Suchasourcedoesn’treallyexist,butitisaveryusefulsimplificaFon
SoundIntensity–PointSourcePointSource:Sothesourceiswhateverisemibngthesound,andweassumethatitcomesfromasinglepointinspace.
=>NOTE:Suchasourcedoesn’treallyexist,butitisaveryusefulsimplificaFon=>Theclosestthingtoimaginewouldbeaverysmallspeakeremibngsound
SoundIntensity–PointSourcePointSource:Sothesourceiswhateverisemibngthesound,andweassumethatitcomesfromasinglepointinspace.
Then,weimaginethatsoundasemanaFngin3-dimensionsoutwardfromthepointsource
hXp://dev.physicslab.org/Document.aspx?doctype=2&filename=WavesSound_DopplerEffectSourceMoving.xml
hXp://dev.physicslab.org/Document.aspx?doctype=2&filename=WavesSound_DopplerEffectSourceMoving.xml
Picturethesourceinthemiddleofaneverexpanding3-dimensionalsphere
SoundIntensity–PointSourceThismeansthatthesurfacethesoundenergyispassingthroughisthesurfaceofthatsphere!
SoundIntensity–PointSourceThismeansthatthesurfacethesoundenergyispassingthroughisthesurfaceofthatsphere!WhatistheequaFonforthesurfaceareaofasphere?
SoundIntensity–PointSourceThismeansthatthesurfacethesoundenergyispassingthroughisthesurfaceofthatsphere!WhatistheequaFonforthesurfaceareaofasphere?
=>4πr2 whereristheradiusofthesphere
SoundIntensity–PointSourceThismeansthatthesurfacethesoundenergyispassingthroughisthesurfaceofthatsphere!WhatistheequaFonforthesurfaceareaofasphere?
=>4πr2 whereristheradiusofthesphereSoIntensity,
I =Power
4⇡r2
IntensityWhathappenstotheintensityofasoundwaveasyoutripleyourdistanceawayfromthesource?A. Increasesby9xB. Increasesby3xC. StaysthesameD. Decreasesby1/3xE. Decreasesby1/9x
IntensityWhathappenstotheintensityofasoundwaveasyoutripleyourdistanceawayfromthesource?A. Increasesby9xB. Increasesby3xC. StaysthesameD. Decreasesby1/3xE. Decreasesby1/9x
Intensity
hXp://hyperphysics.phy-astr.gsu.edu/hbase/AcousFc/invsqs.html
IntensitySothefartherawayyougetfromapointsource,thesameamountofenergygetsspreadoutoveranincreasinglylargesurface.
IntensitySothefartherawayyougetfromapointsource,thesameamountofenergygetsspreadoutoveranincreasinglylargesurface.Thismeansthattheintensityofthesounddecreasesthefartherawayyougetfromthesource.
IntensitySothefartherawayyougetfromapointsource,thesameamountofenergygetsspreadoutoveranincreasinglylargesurface.Thismeansthattheintensityofthesounddecreasesthefartherawayyougetfromthesource.So,inotherwords,theintensityofsoundyouheardependsonhowfarawayyouarefromthesource
IntensitySothefartherawayyougetfromapointsource,thesameamountofenergygetsspreadoutoveranincreasinglylargesurface.Thismeansthattheintensityofthesounddecreasesthefartherawayyougetfromthesource.(Thisisaclassicexampleofan“inversesquarelaw”)
IntensityIfthereismorethanonesourceofsound,thentofindthetotalintensityyouwould…
IntensityIfthereismorethanonesourceofsound,thentofindthetotalintensityyouwould…
=>justaddtheintensiFesfromeachindividualsource!
IntensityIftherewasaguitarplayerjammingwhoproducesanintensityof400W/m2,whatwouldtheintensitybeiftherewere3guitaristplaying?A. 400W/m2B. 403W/m2C. 1200W/m2D. 400,000W/m2E. 64,000,000W/m2
IntensityIftherewasaguitarplayerjammingwhoproducesanintensityof400W/m2,whatwouldtheintensitybeiftherewere3guitaristplaying?A. 400W/m2B. 403W/m2C. 1200W/m2D. 400,000W/m2E. 64,000,000W/m2
PerceivedVolumeofSound
NowwecanuseintensitytotryandquanFfythe“loudness”ofasound.
PerceivedVolumeofSound
NowwecanuseintensitytotryandquanFfythe“loudness”ofasound.“Fun”fact:Perceivedvolumeandintensityare
related…inaweirdway.
PerceivedVolumeofSound
NowwecanuseintensitytotryandquanFfythe“loudness”ofasound.“Fun”fact:Perceivedvolumeandintensityare related…inaweirdway.Ifyouhearasound,andyouperceivethatthesoundhasdoubleditsvolume,thenitsintensityasactuallyincreasedbyafactorof10!!
IntensityIfasingleguitarplayerjammingproducesanintensityof400W/m2,whatwouldtheintensitybeiftheperceivedvolumewasdoubled?A. 402W/m2B. 800W/m2C. 4,000W/m2D. 160,000W/m2E. 4,000,000W/m2
IntensityIfasingleguitarplayerjammingproducesanintensityof400W/m2,whatwouldtheintensitybeiftheperceivedvolumewasdoubled?A. 402W/m2B. 800W/m2C. 4,000W/m2D. 160,000W/m2E. 4,000,000W/m2
IntensityIftherewasaguitarplayerjamming,howmanyguitarplayersjammingwiththesameintensitywouldbeneededtodoubletheperceivedvolume?A. 2B. 4C. 10D. 20E. 100
IntensityIftherewasaguitarplayerjamming,howmanyguitarplayersjammingwiththesameintensitywouldbeneededtodoubletheperceivedvolume?A. 2B. 4C. 10D. 20E. 100
IntensityHowmanyguitarplayersjammingwouldbeneededtodoubletheperceivedvolumeof2guitarplayers?A. 4B. 8C. 14D. 20E. 100
IntensityHowmanyguitarplayersjammingwouldbeneededtodoubletheperceivedvolumeof2guitarplayers?A. 4B. 8C. 14D. 20E. 100
IntensityHowmanyguitarplayersjammingwouldbeneededtohavehalfoftheperceivedvolumeof30guitarplayers?A. 3B. 9C. 10D. 15E. 20
IntensityHowmanyguitarplayersjammingwouldbeneededtohavehalfoftheperceivedvolumeof30guitarplayers?A. 3B. 9C. 10D. 15E. 20
LogarithmsReview
FromAlgebra,whereB=Base:
logB (x) = yBy = x
LogarithmsReview
FromAlgebra,whereB=Base:ThesetwofuncFonsareinversesofeachother
logB (x) = yBy = x
LogarithmsReview
FromAlgebra,whereB=Base:We’llbeusingthemostcommonbase,base10
logB (x) = yBy = x
LogarithmsReview
Fory=1:
101 = 10log10(10) = 1
10y = x
log10(x) = y
LogarithmsReview
Fory=1:Fory=2:
101 = 10log10(10) = 1
log10(100) = 2102 = 100
10y = x
log10(x) = y
LogarithmsReview
Fory=1:Fory=2:Fory=3:
101 = 10log10(10) = 1
log10(100) = 2
log10(1000) = 3
102 = 100
103 = 1000
10y = x
log10(x) = y
LogarithmsReview
Sothegoaloflogarithms:1) Youhaveanumber,like100or53,whichis“x”
10y = x
log10(x) = y
LogarithmsReview
Sothegoaloflogarithms:1) Youhaveanumber,like100or53,whichis“x”2) Youwanttofigureoutwhatexponenttoraise
“10”totogetthatnumber,x,out!
10y = x
log10(x) = y
LogarithmsReview
Sothegoaloflogarithms:1) Youhaveanumber,like100or53,whichis“x”2) Youwanttofigureoutwhatexponenttoraise
“10”totogetthatnumber,x,out!3) Soyouaretryingtosolvefor“y”
10y = x
log10(x) = y
LogarithmsReview
Sothegoaloflogarithms:1) Youhaveanumber,like100or53,whichis“x”2) Youwanttofigureoutwhatexponenttoraise
“10”totogetthatnumber,x,out!3) Soyouaretryingtosolvefor“y”4) Youdothisbyjusttyping“logx”intoyour
calculator,anditwillspitout“y”!
10y = x
log10(x) = y
LogarithmicscalesThismightseemarbitrary,soyoumightwonderwhythisseeminglyrandommathemaFcalfuncFonissouseful.Thekeythatitisnon-linear.
hXp://freemat.sourceforge.net/help/mathfuncFons_log10.html
log10(x) = y
hXp://freemat.sourceforge.net/help/mathfuncFons_log10.html
log10(x) = y
x=10y=1
hXp://freemat.sourceforge.net/help/mathfuncFons_log10.html
log10(x) = y
x=10y=1
x=100y=2
LogarithmicscalesNon-linearfuncFonsarereallyusefulinscience
LogarithmicscalesNon-linearfuncFonsarereallyusefulinscience1) WhenyouhaveaHUGEspreadofdatathat
youwanttorepresentgraphically
LogarithmicscalesNon-linearfuncFonsarereallyusefulinscience1) WhenyouhaveaHUGEspreadofdatathat
youwanttorepresentgraphically
2) WhentheresponseofasystemisNOTlinear
LogarithmicscalesNon-linearfuncFonsarereallyusefulinscience1) WhenyouhaveaHUGEspreadofdatathat
youwanttorepresentgraphically
2) WhentheresponseofasystemisNOTlinearThatlastoneiswhatwearedealingwith.
LogarithmicscalesAgreatexampleistheRichterScaleusedtoquanFfythe“intensity”ofearthquakes.
LogarithmicscalesAgreatexampleistheRichterScaleusedtoquanFfythe“intensity”ofearthquakes.Ifyouhaveanearthquakethatmeasures“7”ontheRichterscale,andanotherearthquakethatmeasures“8”,youhaven’tdoubledintensityorjustaddedonsomeconstant
LogarithmicscalesAgreatexampleistheRichterScaleusedtoquanFfythe“intensity”ofearthquakes.Ifyouhaveanearthquakethatmeasures“7”ontheRichterscale,andanotherearthquakethatmeasures“8”,youhaven’tdoubledintensityorjustaddedonsomeconstantRather,yourintensityhasgoneupbyafactorof
10!
LogarithmicscalesAnearthquakethatmeasures“9”is1000=mesmoreintensethananearthquakethatmeasures“6”
LogarithmicscalesAnearthquakethatmeasures“9”is1000=mesmoreintensethananearthquakethatmeasures“6”Thedecibelscaleisanotherexampleofanon-linearscale,andiswhyI’vebeenbabblingonaboutlogarithms.
LogarithmicscalesAnearthquakethatmeasures“9”is1000=mesmoreintensethananearthquakethatmeasures“6”Thedecibelscaleisanotherexampleofanon-linearscale,andiswhyI’vebeenbabblingonaboutlogarithms.Decibelsmeasurethe“loudness”ofasound
Loudness,βFirstlet’sidenFfythefaintestintensityofsoundhumanscanhear:Io=10-12W/m2
Loudness,βFirstlet’sidenFfythefaintestintensityofsoundhumanscanhear:Io=10-12W/m2So,wecanmeasureloudness,β,as: β=10log(I/Io)
Loudness,βFirstlet’sidenFfythefaintestintensityofsoundhumanscanhear:Io=10-12W/m2So,wecanmeasureloudness,β,as:Theunitofβis:decibels(dB)
β=10log(I/Io)
Loudness,βFirstlet’sidenFfythefaintestintensityofsoundhumanscanhear:Io=10-12W/m2So,wecanmeasureloudness,β,as:Theunitofβis:decibels(dB)=>NOTE:βisNOT“perceivedvolume,”butamathemaFcalquanFtycalled“loudness”
β=10log(I/Io)
β=10log(I/Io)
I=Io:I=10Io:I=100Io:I=1000Io:
β=10log(I/Io)
I=Io:I=10Io:I=100Io:I=1000Io:
� = 10 log(I
o
I
o
) = 10 log(1) = 10 (0) = 0 dB
β=10log(I/Io)
I=Io:I=10Io:I=100Io:I=1000Io:
� = 10 log(I
o
I
o
) = 10 log(1) = 10 (0) = 0 dB
� = 10 log(10I
o
I
o
) = 10 log(10) = 10 (1) = 10 dB
β=10log(I/Io)
I=Io:I=10Io:I=100Io:I=1000Io:
� = 10 log(I
o
I
o
) = 10 log(1) = 10 (0) = 0 dB
� = 10 log(10I
o
I
o
) = 10 log(10) = 10 (1) = 10 dB
� = 10 log(100I
o
I
o
) = 10 log(100) = 10 (2) = 20 dB
β=10log(I/Io)
I=Io:I=10Io:I=100Io:I=1000Io:
� = 10 log(I
o
I
o
) = 10 log(1) = 10 (0) = 0 dB
� = 10 log(10I
o
I
o
) = 10 log(10) = 10 (1) = 10 dB
� = 10 log(100I
o
I
o
) = 10 log(100) = 10 (2) = 20 dB
� = 10 log(1000I
o
I
o
) = 10 log(1000) = 10 (3) = 30 dB
β=10log(I/Io)
Forevery10dBofloudness,theintensityismulFpliedby10andthe“perceivedvolume”doubles!
I=Io:I=10Io:I=100Io:I=1000Io:
� = 10 log(I
o
I
o
) = 10 log(1) = 10 (0) = 0 dB
� = 10 log(10I
o
I
o
) = 10 log(10) = 10 (1) = 10 dB
� = 10 log(100I
o
I
o
) = 10 log(100) = 10 (2) = 20 dB
� = 10 log(1000I
o
I
o
) = 10 log(1000) = 10 (3) = 30 dB
Whatistheloudnessofasoundwithanintensityof1x10-6W/m2?
Whatistheloudnessofasoundwithanintensityof1x10-6W/m2?
Answer:60dB
Thereare4blaringcarhornsproducingatotalsoundof70dB.Whatistheintensityofthissound?
A) 10-7W/m2B) 10-5W/m2C) 1W/m2D) 10W/m2E) 105W/m2F) 107W/m2
Thereare4blaringcarhornsproducingatotalsoundof70dB.Whatistheintensityofthissound?
A) 10-7W/m2B) 10-5W/m2C) 1W/m2D) 10W/m2E) 105W/m2F) 107W/m2
Thereare4blaringcarhornsproducingatotalsoundof70dB.Whatistheintensityofthissound?
A) 10-7W/m2B) 10-5W/m2C) 1W/m2D) 10W/m2E) 105W/m2F) 107W/m2
So,whatistheintensityofoneblaringcarhorn?
Thereare4blaringcarhornsproducingatotalsoundof70dB.Whatistheintensityofthissound?
A) 10-7W/m2B) 10-5W/m2C) 1W/m2D) 10W/m2E) 105W/m2F) 107W/m2
So,whatistheintensityofoneblaringcarhorn?
Answer:0.25x10-5W/m2
Howmanydecibelsisonecarhornblaring?(Wecalculateditsintensitytobe0.25x10-5W/m2)
A) 10dBB) 62dBC) 64dBD) 68dBE) 70dBF) 74dB
Howmanydecibelsisonecarhornblaring?(Wecalculateditsintensitytobe0.25x10-5W/m2)
A) 10dBB) 62dBC) 64dBD) 68dBE) 70dBF) 74dB
Ifyoudoubledthevolumeofoneblaringcarhorn,howmanydecibelsisthat?A. 74dBB. 128dBC. 640dBD. 4096dBE. Noneofthese
Ifyoudoubledthevolumeofoneblaringcarhorn,howmanydecibelsisthat?A. 74dBB. 128dBC. 640dBD. 4096dBE. Noneofthese
Ifyoudoubledthevolumeof4blaringcarhorns,whichproducedatotalof70dB,howmanyhornswouldbeneededandhowmanydecibelswouldthatbe?A. 8horns,140dBB. 8horns,80dBC. 40horns,140dBD. 40horns,80dBE. Noneofthese
Ifyoudoubledthevolumeof4blaringcarhorns,whichproducedatotalof70dB,howmanyhornswouldbeneededandhowmanydecibelswouldthatbe?A. 8horns,140dBB. 8horns,80dBC. 40horns,140dBD. 40horns,80dBE. Noneofthese
Ifyourheadphonesproduced95dB,andthenyouturnedthemdownto75dB,byhowmuchdidtheintensitychange?A. Decreasedto1/4oftheintensityB. Decreasedto1/20oftheintensityC. Decreasedto1/100oftheintensityD. Decreasedto1/200oftheintensityE. Decreasedto1/400oftheintensityF. Decreasedto1/1000oftheintensity
Ifyourheadphonesproduced95dB,andthenyouturnedthemdownto75dB,byhowmuchdidtheintensitychange?A. Decreasedto1/4oftheintensityB. Decreasedto1/20oftheintensityC. Decreasedto1/100oftheintensityD. Decreasedto1/200oftheintensityE. Decreasedto1/400oftheintensityF. Decreasedto1/1000oftheintensity
Torestatethegeneralrules:Youarestandingsomewhere,listeningtoasound.Theperceivedvolumethatyouheardoubles,andthesound’sintensitythatyouexperienceismulFpliedby10,and10dBhavebeenaddedtothesound’sloudness(β)thatyouexperience.
hXps://noiselimiters.co.uk/buy/noise-levels-what-is-noise.php
hXp://sound.whsites.net/arFcles/fadb.htm
DamagetoHearing
hXps://chicagoent.com/dangerous-decibels-how-loud-is-too-loud/
DamagetoHearing
hXps://chicagoent.com/dangerous-decibels-how-loud-is-too-loud/
Regularearbudscanreachupto115dB,theyshouldbesetat85dB
hXp://www.sightandhearing.org/Store/tabid/999/ProdID/1/
Default.aspx
SomeGuinnessBookofWorldRecords
DopplerEffect
SofarwehaveassumedthatthesourceofthesoundhasbeenstandingsFll.
DopplerEffect
SofarwehaveassumedthatthesourceofthesoundhasbeenstandingsFll.WehavealsoassumedthatyoudetecFngthesoundhavealsobeenstandingsFll.
hXp://dev.physicslab.org/Document.aspx?doctype=2&filename=WavesSound_DopplerEffectSourceMoving.xml
hXp://dev.physicslab.org/Document.aspx?doctype=2&filename=WavesSound_DopplerEffectSourceMoving.xml
Source
hXp://dev.physicslab.org/Document.aspx?doctype=2&filename=WavesSound_DopplerEffectSourceMoving.xml
SourceDetector
DopplerEffect
SofarwehaveassumedthatthesourceofthesoundhasbeenstandingsFll.WehavealsoassumedthatyoudetecFngthesoundhavealsobeenstandingsFll.However,whathappenswhenone(orboth)aremoving??
hXp://www.school-for-champions.com/science/waves_doppler_effect.htm#.WK2qwhiZPVo
Source
hXp://www.school-for-champions.com/science/waves_doppler_effect.htm#.WK2qwhiZPVo
Ifdetectorishere
Source
hXp://www.school-for-champions.com/science/waves_doppler_effect.htm#.WK2qwhiZPVo
Ifdetectorishere
Source
hXp://www.school-for-champions.com/science/waves_doppler_effect.htm#.WK2qwhiZPVo
Ifdetectorishere
Source
Ifdetectorishere
hXp://www.school-for-champions.com/science/waves_doppler_effect.htm#.WK2qwhiZPVo
Ifdetectorishere
Source
Ifdetectorishere
DopplerEffectWhenthesourceismovingtowardsyou,thewavesget“squishedtogether,”resulFnginashorterwavelengthandahigherpitch.Whenthesourceismovingawayfromyou,thewavesget“stretchedout,”resulFnginalongerwavelengthandalowerpitch.
DopplerEffectWhenthesourceismovingtowardsyou,thewavesget“squishedtogether,”resulFnginashorterwavelengthandahigherpitch.Whenthesourceismovingawayfromyou,thewavesget“stretchedout,”resulFnginalongerwavelengthandalowerpitch.Note:ThisdoesNOTaffectthevolumeofthesound,justthewavelength/pitch
DopplerEffect
Screechingcarhorn:hXps://www.youtube.com/watch?v=a3RfULw7aAYEuropeansiren:hXps://www.youtube.com/watch?v=imoxDcn2Sgo
DopplerEffect
ThesamethinghappensifthesourceisstaFonaryandyou(thedetector)aremoving.Ifyouaremovingtowardthedetector,then…
DopplerEffect
ThesamethinghappensifthesourceisstaFonaryandyou(thedetector)aremoving.Ifyouaremovingtowardthedetector,then…thepitchyouheargetshigher
DopplerEffect
ThesamethinghappensifthesourceisstaFonaryandyou(thedetector)aremoving.Ifyouaremovingtowardthedetector,then…thepitchyouheargetshigherIfyouaremovingawayfromthedetector,then…
DopplerEffect
ThesamethinghappensifthesourceisstaFonaryandyou(thedetector)aremoving.Ifyouaremovingtowardthedetector,then…thepitchyouheargetshigherIfyouaremovingawayfromthedetector,then…thepitchyouheargetslower.
DopplerEffect
DopplerEffectinAstronomy=>Redshiw
DopplerEffect
DopplerEffectinAstronomy=>Redshiw
hXps://www.quora.com/How-does-the-Doppler-effect-prove-that-the-universe-is-expanding
DopplerEffectForwhichobjectistheDopplerEffectgoingtobedemonstratedinamoredrasFcway(greaterchangeinfrequency)?A. AnobjectemibngaloudersoundB. AnobjectmovingfasterC. AnobjectemibngahigherpitchsoundD. Allofthese
DopplerEffectForwhichobjectistheDopplerEffectgoingtobedemonstratedinamoredrasFcway(greaterchangeinfrequency)?A. AnobjectemibngaloudersoundB. AnobjectmovingfasterC. AnobjectemibngahigherpitchsoundD. Allofthese
WhistleswereputonbombsthatweredroppedfromairplanesinWWIIasameansofpsychologicalwarfare.Whenrecordedfromtheplaneasabombfell,itsoundedlikethis:Why?hXp://soundbible.com/30-Bomb-Dropping.html hXp://www.youtube.com/watch?v=cGigkA-Xh5E
A. ItwasmovingawayfromtheplaneB. ItwasspeedingupC. BothA&BD. ItwasfallingdownE. Itwasmadetosoundlikethat
WhistleswereputonbombsthatweredroppedfromairplanesinWWIIasameansofpsychologicalwarfare.Whenrecordedfromtheplaneasabombfell,itsoundedlikethis:Why?hXp://soundbible.com/30-Bomb-Dropping.html hXp://www.youtube.com/watch?v=cGigkA-Xh5E
A. ItwasmovingawayfromtheplaneB. ItwasspeedingupC. BothA&BD. ItwasfallingdownE. Itwasmadetosoundlikethat
DopplerEffectIfyouwereonthegroundasawhistlingbombapproachedyouawerbeingreleasedfromaplane,whatwouldyouhearbeforethebombhittheground?A. Adecreasingpitch(justlikewejustheard)B. AconstanthigherpitchC. Anincreasingpitch(reversetowhatwejust
heard)D. Nothing
DopplerEffectIfyouwereonthegroundasawhistlingbombapproachedyouawerbeingreleasedfromaplane,whatwouldyouhearbeforethebombhittheground?A. Adecreasingpitch(justlikewejustheard)B. AconstanthigherpitchC. Anincreasingpitch(reversetowhatwejust
heard)D. Nothing
Aspeakerisatrestatthesideofastraightroad.Thespeakerproducesasteadysoundofconstantfrequency.AstudentisstandingsFllnearthespeaker.Twovehiclesaredrivendowntheroad:atruckapproachingthespeakerandacarmovingawayfromthespeaker.Ifthesoundisrepresentedbywavefronts,thestudentandthevehicledriverseachobserveadifferentamountofFmebetweensuccessivewavefronts:tsforthestudent,ttforthetruckdriver,andtcforthecardriver.WhichofthefollowingcorrectlyrankstheFmes?
A)ts<tt<tcB)tc<ts<ttC)tt<ts<tcD)tt<tc<ts
Aspeakerisatrestatthesideofastraightroad.Thespeakerproducesasteadysoundofconstantfrequency.AstudentisstandingsFllnearthespeaker.Twovehiclesaredrivendowntheroad:atruckapproachingthespeakerandacarmovingawayfromthespeaker.Ifthesoundisrepresentedbywavefronts,thestudentandthevehicledriverseachobserveadifferentamountofFmebetweensuccessivewavefronts:tsforthestudent,ttforthetruckdriver,andtcforthecardriver.WhichofthefollowingcorrectlyrankstheFmes?
A)ts<tt<tcB)tc<ts<ttC)tt<ts<tcD)tt<tc<ts
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