- #1
Cheman
- 235
- 1
Standing waves on strings...
I understand how to produce standing waves on a string when we have a vibrator at one end, as you usually use in demonstrations in physics classes. ie - increase frequencies until we achieve the correct kind of interference to produce standing wave.
However, it i when we apply this to talking about how a stringed instrument, let's say a guitar, works that I begin to ask questions. Here we go:
i) We pluck the string - how does that initiate the standing wave? Does it set of transverse waves in both directions (ie - towards both fixed ends) which then reflect to form standing wave?
ii) What frequency does the string vibrate at? In the demonstration I mentioned, we chose the frequency the string vibrates at, so what frequency does this "ungoverned" string vibrate at? And how do we know this should produce at least the fundamental frequency?
iii) Why do we get complex wave forms? ie - not just fundamental frequency? Is it because we do not get perfect interference so the standing waves are not "perfect"? And how come we can describe these as if they are just mixtures of the harmonic frequencies?
If anyone can answer these questions i would be most greatful.
Thanks in advance.
I understand how to produce standing waves on a string when we have a vibrator at one end, as you usually use in demonstrations in physics classes. ie - increase frequencies until we achieve the correct kind of interference to produce standing wave.
However, it i when we apply this to talking about how a stringed instrument, let's say a guitar, works that I begin to ask questions. Here we go:
i) We pluck the string - how does that initiate the standing wave? Does it set of transverse waves in both directions (ie - towards both fixed ends) which then reflect to form standing wave?
ii) What frequency does the string vibrate at? In the demonstration I mentioned, we chose the frequency the string vibrates at, so what frequency does this "ungoverned" string vibrate at? And how do we know this should produce at least the fundamental frequency?
iii) Why do we get complex wave forms? ie - not just fundamental frequency? Is it because we do not get perfect interference so the standing waves are not "perfect"? And how come we can describe these as if they are just mixtures of the harmonic frequencies?
If anyone can answer these questions i would be most greatful.
Thanks in advance.