Final answer:
The fundamental frequency of the tube is 254 Hz and the frequency of its second harmonic is 508 Hz.
Step-by-step explanation:
The fundamental frequency of a tube open at both ends can be calculated using the formula:
f = v / (2L)
where f is the frequency, v is the speed of sound, and L is the length of the tube.
In this case, the length of the tube is 0.672 m and the speed of sound is 344 m/s.
Plugging in these values, we get:
f = 344 / (2 * 0.672) = 254 Hz
The second harmonic is twice the fundamental frequency, so:
second harmonic = 2 * 254 = 508 Hz