Well water would prob be your best bet, you could extract the salt first and then use a magnet to seperate the iron filing from the sand
Answer:
168 Hz, 280 Hz and 392 Hz
Explanation:
The resonant frequencies for a closed pipe at one end is given by :
, n = 1,3,5...
The fundamental frequency, f₁ = v/4l = 56 Hz
For first overtone, put n = 3
![f_3=\dfrac{3v}{4L}\\\\=3\times \dfrac{v}{4L}\\\\=3\times 56\\\\=168\ Hz](https://tex.z-dn.net/?f=f_3%3D%5Cdfrac%7B3v%7D%7B4L%7D%5C%5C%5C%5C%3D3%5Ctimes%20%5Cdfrac%7Bv%7D%7B4L%7D%5C%5C%5C%5C%3D3%5Ctimes%2056%5C%5C%5C%5C%3D168%5C%20Hz)
For second overtone, put n = 5
![f_5=5\times f_1\\\\=5\times 56\\\\=280\ Hz](https://tex.z-dn.net/?f=f_5%3D5%5Ctimes%20f_1%5C%5C%5C%5C%3D5%5Ctimes%2056%5C%5C%5C%5C%3D280%5C%20Hz)
For third overtone, put n = 7
![f_7=7\times f_1\\\\=7\times 56\\\\=392\ Hz](https://tex.z-dn.net/?f=f_7%3D7%5Ctimes%20f_1%5C%5C%5C%5C%3D7%5Ctimes%2056%5C%5C%5C%5C%3D392%5C%20Hz)
So, the first three overtones are 168 Hz, 280 Hz and 392 Hz.
C. The Uniformity of Cosmic Background Radiation