Calculate fundamental overtone and length of tube

1. Jun 2, 2013

bookerdewitt

1. The problem statement, all variables and given/known data
It is observed that a tube open at both ends exhibits harmonics at 438 Hz, 584 Hz, and 730 Hz.
A) Calculate the fundamental overtone of the tube.
B) Calculate the length of the tube.

2. Relevant equations
L=lambda/2 x n, v = f x lambda

3. The attempt at a solution
I know that the fundamental overtone is the second harmonic so n would be 2 but to calculate the frequency I would need to know the velocity and wavelength and I don't see how I can get those.

2. Jun 2, 2013

JustinEFE

A)Well, in this instance, you are given three consecutive harmonics at 438Hz, 584Hz, and 730Hz. Besides the equations that you are given, you also know that harmonics in this open tube are integer multiples of the fundamental frequency. So, you can easily calculate the difference between each of the given frequencies to find the fundamental harmonic. From there, you can find the first overtone by multiplying the fundamental frequency by 2.

3. Jun 2, 2013

JustinEFE

B) For this part, it looks like they want you to assume the speed of sound to be 343m/s (speed of sound in air at 20°C). If this is the case, then your calculations should be relatively simple.

4. Jun 2, 2013

bookerdewitt

Thanks a lot.