Sometimes, when the wind blows across a long wire, a low-frequency \"moaning\" s

Question

Sometimes, when the wind blows across a long wire, a low-frequency "moaning" sound is produced. The sound arises because a standing wave is set up on the wire, like a standing wave on a guitar string. Assume that a wire (linear density = 0.0185 kg/m) sustains a tension of 302 N because the wire is stretched between two poles that are 15.97 m apart. The lowest frequency that an average, healthy human ear can detect is 20.0 Hz. What is the lowest harmonic number n that could be responsible for the "moaning" sound? n =

Explanation / Answer

Speed of the wave along the wire

v = sqrt(tension/density)

v = sqrt(302/0.0185)

v = 127.766679 m/s

Length of the wire = 0.5 wavelength (node at each end)
so wavelength = 31.94 m

Fundamental frequency = wavespeed/wavelength

F1 = 4.00021 Hz

so 20 Hz is the 20/4.00 = 5th harmonic.

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.