Answer:
a. v = 355.68 m / s
b. fₙ = 156 Hz
Explanation:
Given
L = 0.570 m , f = 780 Hz
f = n * v / 4 * L
Solve to u' to find the speed of sound in the unknown gas
v = f * 4 * L / n
v = 780 Hz * 4 * 0.570 m / 5
v = 355.68 m / s
The fundamental frequency for this pipe when it is filled with the unknown gas
fₙ = f /n
fₙ = 780 Hz / 5
fₙ = 156 Hz