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Review T3 Part 2B
1)Whatisthefundamentalfrequencyofthewaveproducedbythe1.25meterlongwire?
1
(cid:96) = λ
2
1
1.25m = λ
2
λ = 2.5m
2) The tension on the wire shown above is 46.0N. The wire has a linear density of 0.005kg
permeter. Whatisthefrequencyofthesoundproducedbythewire?
(cid:114)
tension
v =
lineardensity
fλ = v
(cid:114)
tension
fλ =
lineardensity
(cid:114)
46N
f(2.5) =
0.005kg/m
f= 38.4Hz
3)Whatisthefundamentalfrequencyofthe1.32meterlongpipewhichisclosedatoneend?
1
(cid:96) = λ
4
4(cid:96) = λ,soλ = 5.28m
v = fλ
v 340m/s
f = =
λ 5.28m
f= 64.4Hz
4)Ifthetubeaboveproducesthefifthharmonic,whatisthewavelengthofthewaves?
5
(cid:96) = λ
4
1
4
(cid:96) = λ
5
4
(1.32m) = λ
5
λ= 1.06m
5)Whatisthefrequencyofthefifthharmonic?
v = fλ
v
f =
λ
340
f =
1.06m
f= 322Hz
6)Whatisthefundamentalfrequencyofthe1.32meterlongpipeopenatbothends?
1
(cid:96) = λ
2
2(cid:96) = λ,soλ = 2.64m
v = fλ
v
f =
λ
340m/s
f =
2.64m
f= 129Hz
7)WhatisthefrequencyofthethirdOVERTONEtheopentubeabovewillproduce?
4
(cid:96) = λ
2
1
((cid:96)) = λ,soλ = 0.66m.
2
v = fλ
v
f =
λ
2
340m/s
f =
0.66m
f= 515Hz
8) What beat frequency would be produced if the two pipes (playing their fundamental fre-
quencies)areplayedatthesametime?
f = |f −f |
b 1 2
f = |64.4Hz−129Hz|
b
f = 65Hz
b
9) A radio station transmits waves that have a wavelength of 2.956 meters. What would you
havetotuneyourcarradiotolistentothisstation?
v = fλ
v
f =
λ
3×108m/s
f =
2.956m
f= 101Hz
10)Whatistherangeofhumanhearing?
Therangeisapproximately20Hzto20kHz.
11) When a 256Hz tuning fork is struck simultaneously with an unknown fork 5 beats are
heard in 1 second. A small piece of gum is added to the unknown fork and the experiment
is repeated but now 3 beats are heard each second. What is the natural frequency of the
unknownfork?
f = |f −f |
b 1 2
5Hz = |256Hz−f |
2
The second fork either has a frequency of 261Hz or 251Hz. Adding gum decreases the
frequencyofthetuningfork,makingitcloserinvalueto256Hz,soitmustbegreaterthan
256Hz. Therefore,theunkownforkhasafrequencyof261Hz.
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