# Homework Help: Calculate open pipe length given resonance.

1. Apr 25, 2012

### seker

1. The problem statement, all variables and given/known data

What length of open pipe is needed to give resonance to a 384 Hz sound? Assume the speed of sound to 343 m/s.

2. Relevant equations

$$f=\frac{nv}{2l}$$

3. The attempt at a solution

I am lost as to how to even start this problem.

2. Apr 25, 2012

### tiny-tim

welcome to pf!

hi seker! welcome to pf!

what is the (shortest) length (of an open pipe) needed to give a particular wavelength?

3. Apr 25, 2012

### seker

This is what I have come up with so far.

$$(384)(l)=\frac{(1)(343)}{2}$$

l=9.45m

4. Apr 26, 2012

### tiny-tim

looks ok!

(btw, do you understand why there's a "2" on the bottom, and would you be able to work it out for yourself in an exam if you couldn't remember the exact formula? )