A string has a mass per unit length of 9 10–3 kg/m. What must be the tension in the string if its second harmonic has the same frequency as the second resonance mode of a 2m long pipe open at one end? The length of the string is 1.5 m.

this is my solution


i just want to ask if my second resonance mode understanding is correct.


closed as too localized by Qmechanic Feb 15 '13 at 15:37

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    $\begingroup$ What specifically do you suspect you might be doing incorrectly? $\endgroup$ – David Z Feb 15 '12 at 17:56

I did the calculation without first looking at yours (to make sure I wasn't influenced by any mistakes you might have made!) and got the same result, which is reassuring as I first learned this physics 35 years ago :-).

This is obviously a homework problem. I wonder if the point your professor is trying to make is that the first overtone of the string is double the frequency of the fundamental, but the first overtone of a closed pipe is three times the frequency of the fundamental.

  • $\begingroup$ tnx bro. 35 years wow $\endgroup$ – WantIt Feb 16 '12 at 11:05
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    $\begingroup$ You'll be that old one day, and if I'm not dead I'll laugh :-) $\endgroup$ – John Rennie Feb 16 '12 at 11:20

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