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Questions tagged [string]

This tag is for non-relativistic material strings, such as, e.g., a guitar string. PLEASE DO NOT USE THIS TAG for relativistic strings and string theory.

This tag is for non-relativistic material strings, such as, e.g., a guitar string. PLEASE DO NOT USE THIS TAG for relativistic strings and string theory.

1327 questions
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Why are the harmonics of a piano tone not multiples of the base frequency?

I was trying to figure out which piano keys were being played in an audio recording using spectral analysis, and I noticed that the harmonics are not integer multiple of the base note. What is the reason for this? Take a look at the spectrogram of…
Szabolcs
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104
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9 answers

Which is stronger, a rope without knots or a rope with knots?

Suppose I have two identical ropes, one of which I manually tie some knots in. If I use them to hang clothes, which one is more durable? Personally I think that rope with knots will be more durable, but I can't come up with a satisfactory reason.
an offer can't refuse
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Why is the shape of a hanging chain not a "V"?

From Wikipedia: To answer this question: "What is the shape of a chain suspended at both ends?" we can use the variational principle that the shape must minimize the gravitational potential energy. The gravitational potential energy is highest at…
Jossie Calderon
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48
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1 answer

Why do earphone wires always get tangled up in pocket?

What is the reason? Is it caused by their narrow shape, the soft material, walking vibration or something else?
gerry
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47
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10 answers

Why do string instruments need hollow bodies?

My textbook states, 'The sound box has a large area, it sets a large volume of air into vibration, the frequency of which is same as that of the string. So due to resonance a loud sound is produced.' My question is why isn't the air around the…
Hayden Soares
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32
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7 answers

Why won't a tight cable ever be fully straight?

I posted this picture of someone on a zipline on Facebook. One of my friends saw it and asked this question, so he could try to calculate the speed at which someone on the zipline would be going when they hit the water. The only answer, which was…
Tango
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32
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7 answers

Why do higher harmonics have a lower amplitude than the fundamental frequency?

When we pluck a string, it vibrates in all possible modes of vibrations. The lowest frequency possible is the fundamental frequency and it is the most significant part of sound. But why do the amplitude of higher harmonics decrease? Which formula is…
Rahul R
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31
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4 answers

How can transverse waves on a string carry longitudinal momentum?

In general, if a wave carries energy density $u$ with velocity $v$, it also carries momentum density $u/v$. I've seen this explicitly shown for electromagnetic waves and (longitudinal) sound waves. However, I'm having trouble seeing how the momentum…
knzhou
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29
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4 answers

How does a violin produce notes, microscopically?

I believe this question would have been asked before, but not like this. The popular answer to this question is that the slide-release action of a bow sets up vibrations in the strings, of which ultimately only the resonant frequencies would…
AlphaLife
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27
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10 answers

Why I think tension should be twice the force in a tug of war

I'm going to provide my argument for why I think the tension in a rope should be twice the force exerted on either side of it. First, let's consider a different example. Say there is a person named $\text{A}$ and a block in space. $\text{A}$ pushes…
Alraxite
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25
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4 answers

Why does the curve of a hanging chain not minimize the area below it?

If we have a chain of fixed length hanging from two points we know that it will form a curve that minimizes the chain's potential energy. If we imagine the chain as having many small segments, then the potential energy of each segment is $E_p =…
jan
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23
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4 answers

Magnetic field changes induced by vibrating electric guitar string

Here is a picture (from a paper by Feinberg and Yang in the Journal of the Acoustical Society of America) of an electric guitar string vibrating (mostly in the $y$ dimension) near a permanent magnet. The steel guitar string is causing the magnetic…
Wandering Logic
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23
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3 answers

What happens to an astronaut (with a long rope trailing behind him), when he crosses the event horizon of a black hole?

Let's assume there is an astronaut with a very long rope trailing behind him. As he approaches a very large black hole, he can look back and see the rope behind him trailing off into the distance. What would he see after he crosses the event horizon…
Andrew
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23
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5 answers

Wave reflection and open end boundary condition intuition

I need to understand one seemingly simple thing in wave mechanics, so any help is much appreciated! When a pulse on a string travels to the right toward an open end (like a massless ring that is free to oscillate only along the vertical direction),…
TheQuantumMan
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23
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5 answers

Why do harmonics occur when you pluck a string?

When you energise a taut string, the following resonant modes of vibration occur: Plotting on the frequency domain, you can see their corresponding frequencies: But what is the underlying physical principle? Why does this happen? Is there any way…
P i
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