GR0177 #50


Problem


This problem is still being typed. 
Wave Phenomena}Sound
Since the wavelength of the wave does not change, as the pipe presumably stays approximately the same length, only the frequency varies. If the speed of sound changes, then the frequency changes. If the speed of sound is lower than usual, then the frequency is lower. Thus, choices (A), (B) and (C) remain. Calculate to get choice (B).


Alternate Solutions 
uhurulol 20141020 18:24:42  If you're looking for a more mathematical answer, use the simple relation
=
Note that is just , and as such
= .
cancels on both sides and , so plugging everything in and cancelling we have
Cross multiply to obtain , as in choice (B). Hope this helps.   dham 20101006 23:07:59  For a quick guess: Cold instruments go flat. (Frequency goes down), leaving choices AC.
Directly: c=f, so speed of sound is directly proportional to wavelength.
Find the change in wavelength by finding (440)=3*4.4.
That's little over 12.
44012=428, which is a little over 427 (B).
B is the right answer.  

Comments 
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kevintah 20151005 23:39:49 
Some how the Latex got distorted, and I can\'t edit it . Oh well

  uhurulol 20141020 18:24:42  If you're looking for a more mathematical answer, use the simple relation
=
Note that is just , and as such
= .
cancels on both sides and , so plugging everything in and cancelling we have
Cross multiply to obtain , as in choice (B). Hope this helps.   jwbrooks0 20140922 21:21:30  I'm confused. The speed of sound should be proportional to the sqrt(T). http://en.wikipedia.org/wiki/Speed_of_sound#Speed_in_ideal_gases_and_in_air
Therefore, why isn't 440*sqrt(0.97) = 433 correct?
Stardust 20151022 15:37:18 
The question says the \'SPEED OF SOUND is 3% lower than...\' not the temperature.

  dham 20101006 23:07:59  For a quick guess: Cold instruments go flat. (Frequency goes down), leaving choices AC.
Directly: c=f, so speed of sound is directly proportional to wavelength.
Find the change in wavelength by finding (440)=3*4.4.
That's little over 12.
44012=428, which is a little over 427 (B).
B is the right answer.   f4hy 20091106 23:27:57  They give you the 20 degrees as a trick then?
dham 20101006 23:09:25 
Not really, it's just an initial condition.

  michealmas 20061230 11:48:37  use the equation relating freq., velocity, and wavelength.   nahmad 20060330 22:21:27  One quick way of doing this calculation in your head is to consider it as a 3% loss. Thus 3 for every 100, which gives a loss of 12. 44012 = 428.  

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