Tell me more ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.
up vote -1 down vote favorite

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

http://screensnapr.com/e/u4kvtH.png

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

share|improve this question
1  
What specifically do you suspect you might be doing incorrectly? – David Zaslavsky♦ Feb 15 '12 at 17:56

closed as too localized by Qmechanic♦ Feb 15 at 15:37

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, see the FAQ.

1 Answer

up vote 0 down vote accepted

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.

share|improve this answer
tnx bro. 35 years wow – vvavepacket Feb 16 '12 at 11:05
You'll be that old one day, and if I'm not dead I'll laugh :-) – John Rennie Feb 16 '12 at 11:20

Not the answer you're looking for? Browse other questions tagged or ask your own question.