A stretched string of length $L = 1\text{ m}$ and mass $m = 10\text{ g}$ is under tension $T = 400\text{ N}$. Find fundamental frequency and frequency of 3rd harmonic.
2.
A organ pipe closed at one end has fundamental frequency $250\text{ Hz}$. Find length of the pipe if speed of sound is $340\text{ m/s}$.
