# Homework Help: Sound Intensity

1. Sep 26, 2004

### falcon0311

I'm given two things:

frequency, f = 313 Hz
intensity, I = 1.13 uW/m^2 (microWatts per square meter)

I'm supposed to find the amplitude of the air vibrations caused by this sound.

As always, a push in the right direction is greatly appreciated.

2. Sep 26, 2004

### Sirus

You need a formula; do you have any? Unfortunately the formulas for this stuff are big and complex.

3. Sep 26, 2004

### falcon0311

1......v( delta Pm )^2
- * ------------------- = I
2...............B

I think what I'm seeking is sm, in which case

sm = (delta Pm) / (kB) [k is from (kx - wt)]

Anyone know a program or website that lets me type scientific equations? This spacing stuff gets old fast.

If I work those formulas around, I think I get:

I / k = (1/2)(v)(delta Pm)*sm

The problem there is I don't know what (delta Pm) would be.

Last edited: Sep 26, 2004
4. Sep 26, 2004

### falcon0311

I'm not really sure that whole equation is necessary, but I'm also not sure how to shorten it and figure it out with the two variables given.

5. Sep 26, 2004

### Sirus

We do math typesetting on here using a code called Latex. See the sticky about it in General Physics. Sorry, I'm not very familiar with these formulas. Someone will chime in and help! ;)