- #1

diracdelta

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## Homework Statement

Open and closed pipe, give 5 beats per second.

Open pipe is 30 cm long and gives a tone of frequency f

_{0}.

Speed of sound is 330 m/s.

How long do we need to extend closed pipe so both pipes give equal frequencies?

## Homework Equations

Open pipe, f

_{n}=n*f

_{1}, f

_{1}=v/(2L)

Closed pipe; f

_{n}= f*f

_{1}, f

_{1}= v/(4L)

f

_{beat}= f

_{2 }- f

_{1}

## The Attempt at a Solution

For open pipe, I assume that f

_{0}is f

_{1}, or basic frequency.

f=v/2L=330 ms

^{-1}/ 0,6 m = 550 Hz

f

_{beat}= f

_{2 }- f

_{1}

5 = f

_{2}- 550 Hz

f

_{2}= 555 Hz.

Now we need to find the length of open pipe.

4L = v/f

_{2}

l= v/4f

_{2}= 0,15 m

Since i have the length of closed pipe, motive is to adjust it so we have frequency of 550 Hz.

4L = v/f

_{2},

4*L = 330 ms

^{-1}/ 550 Hz

4*L = 0,6 m

L = 0,15

What did I do wrong?