Hey guys, I'm gapping on these questions.. If you could help that would be great

1)Calculate the frequency of an open pipe that is 36cm long at 15 degrees C

2) Calculate the frequency of a closed pipe that is 18cm long at 30 degrees C

3) A wave with a frequency of 3Hz interferes with a wave that has a frequency of 10Hz. Calculate the beat frequency

4) What frequency would you expect from blowing across the top of an empty soda bottle that is 26cm tall? (Assume room temperature of 20 degrees C)

5) From the question above, what would the frequency be if the soda bottle was one quarter full of soda?

I'm willing to give someone 2.85FG which is nothing at all but I don't have much to bribe you with

Thanks in advance, these probably would be simple but my minds just been blank as I was celebrating my birthday yesterday

It's literally the same question 4 different ways, and a beat frequency question.

Go find an example in your book.

I don't have the text book at the moment or I would, but if you don't have the answer then why post

I know that the formula has to do with 344m/s and such
just I'm having a real brain fart and can't seem to get back on track with what i'm trying to do.

This post was edited by Dunner on Oct 27 2013 08:33pm

Wikipedia should have the formulas you need if you don't have your book on you. I don't remember them off the top of my head, but the Beat Frequency one is very straightforward.

Beat frequency = |f1 - f2| <-- absolute value of difference of the frequencies.

I was kind of hoping you would google and come up with what I did in 10 seconds. :\

v would of course be the speed of sound

The speed of sound varies with temperature in the following equation:

a = sqrt(gamma*R*T) where R is the specific gas constant (287 J/kg-K for air), gamma is ratio of specific heats (1.4 for air), and T is the absolute temperature in Kelvin

Find speed of sound for each problem that temperature is given (add 274 to Celsius for Kelvin).





This post was edited by Dontrunaway on Oct 27 2013 09:53pm

I found this page, I just don't remember doing for any questions done in class
e;/ Because i've tried this and the answer i got was not any of the answers given in multiple choice

e;/// Nevermind, I found where I was going wrong. Thanks for the input/help



This post was edited by Dunner on Oct 27 2013 10:54pm