Question

a) An organ pipe open at both ends has a radius of 4 cm and a length of 5 m. What is the frequency (in Hz) of the third harmonic?.

b) Calculate the frequency of sound you would hear as you drove at 15m/s toward a sound source emitting a sound of frequency 400 Hz.

Answer 1

(a) $f=nv/(2L)=3\cdot344/(2\cdot5)=103.2\ (Hz)$

(b) $f=f_0(1+u/c)=400\cdot(1+15/344)=417.4\ (Hz)$