Questions tagged [vibrations]

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1answer
666 views

The inverse square law of sound through solids?

We all know about the inverse square law of sound. In short the power of the wave will get evenly spread on an ever increasing spherical expansion and this will dissipate the power of the wave at a ...
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1answer
4k views

What frequency of sound waves produces the most vibration [closed]

The name of the question is rather contradictory and counter-intuitive since sound is produced by vibration. However, very low frequencies around 32Hz and receding are bass. From what I have read ...
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2answers
230 views

Forced vibration

Let's consider a spring which is subjected to forced vibrations: $$ F = F_0 \cos(\omega t) $$ Is the resonance frequancy $\omega_0$ of the spring dependent on the amplitude $F_0$? I ask this ...
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1answer
218 views

Why does a minor vertical vibration cause my coffee to spill?

When I walk my kid sometimes I put a cut of coffee in a cupholder attached to the stroller. When I push the stroller over a brick pavement it seems to vibrate vertically. That is enough for the coffee ...
445
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4answers
53k views

Can I compute the mass of a coin based on the sound of its fall?

Other day, I bumped my bookshelf and a coin fell down. This gave me an idea. Is it possible to compute the mass of a coin, based on the sound emitted when it falls? I think that there should be a ...
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2answers
1k views

How to use an accelerometer to correctly quantify the magnitude of vibrations

Consider the following setup: An accelerometer is placed inside a helicopter, measuring $g$ values along three axes $(x,y,z)$ every $10~\text{ms}$ (100 times a second), during a helicopter flight. ...
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2answers
968 views

Finding the components of the tensor for potential and kinetic energy

I have a rather poor understanding of what a tensor is, but enough to apply it to the biggest part of the classical mechanics I'm studying. However, I've run into a small problem while studying "Free ...
29
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4answers
10k views

Why does a large train cause the ground to shake?

I work in a 4 story building that is approx. 150 feet away from a set of train tracks. When a large (40+ car) freight train goes by, the shaking in the building is perceptible. As I've watched the ...
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1answer
69 views

Vibration in a broken cylinder

The physics S.E. may be wrong for this question, but I wonder what happens to a vibration in broken, cracked, or otherwise damaged cylinder. Say you have a 1 meter long steel cylinder, you break it in ...
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1answer
67 views

Why would a screen(with touch controls) in a vibrating environment be readable if its refresh rate is dynamically matched with vibrations?

So, I was reading about this Dragon V2 and it has got touch controlled screens, but screen might be unreadable for pilots because of engine vibrations and whatnot. I came across this comment on reddit....
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1answer
279 views

How Sound of Mobile Vibration travels through wire of Earphones

This may sound dumb, but I have been observing that, If my mobile phone is placed on the wire of my hands free (earphones) and if my mobile vibrates, I could listen the vibration from the ear plugs. I ...
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1answer
101 views

String vibration

In many textbooks an illustration of a vibrating string at a fundamental mode shown (and wikipedia) shown like this http://en.wikipedia.org/wiki/File:Standing_waves_on_a_string.gif). However if you ...
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5answers
10k views

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 ...
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2answers
92 views

Do Baryons have Quantized Vibrational and Rotational States?

Given that baryons are not point particles but are composed of three quarks, are there quantized vibrational and rotational states analogous to those of molecules? If not why not, and if so are ...
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0answers
188 views

De-excitation and vibrational frequency

By utilising energetic beams of particles it is possible to set atomic nuclei into vibration. For a certain nucleus the subsequent de-excitation results in the emission of photons of energy $1$ $MeV$. ...
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1answer
103 views

If I had a 1cm iron sphere that I could vibrate at an rate, how fast would it have to be vibrating before it could not perceived by sense of touch?

Is there a vibratory rate at which my hand would just pass right through the object and it could not be perceived by touch anymore?
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1answer
272 views

Vibration transmission using spring and damper model [closed]

I want to simulate the vibration transmission between two colliding objects. I use a Finite Element Model to simulate the vibration on each object, but I haven't found any good mathematical model to ...
1
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1answer
298 views

What is the physical origin of acoustic modes in a duct?

Lets deal with wave propagation in a cylindrical duct. We ask the question: "what is the general form of a pressure wave which can propagate through the duct?" In answering this, we assume that the ...
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3answers
149 views

How does ultrasonic horn produce a convection current in the water?

When I was using ultrasonic horn in a beaker, I notice that there are convection currents in the beaker and stir up my substance. I don't understand why it produce water current, I thought that it ...
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1answer
660 views

Resonance and the driving frequency?

Why does resonance occur in a mass-spring system when the natural frequency = the driving frequency. I think it is because the driving force is always contributing to the kinetic energy of the system ...
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2answers
3k views

Frequency of touch, taste, and scent [closed]

So I was thinking about sound - and how anything below 20Hz is basically inaudible to humans (because it is too low of a frequency to be recognized), as well as anything above around 20KHz (because it ...
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0answers
938 views

Saddle point and transition state of a molecule

During a transition of a molecule from one state to another, it pass through a transition state. This transition state, mathematically speaking, is a saddle point. That means, the second derivative ...
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1answer
137 views

Two coffee beans in a cup of water + vibrations = gravity? [duplicate]

If you float two coffee beans in a cup of water that is being vibrated by your subwoofer (go to a sin wave generator online), the two beans will either be attracted to the sides of the cup or if ...
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1answer
4k views

How do I recover the 1D wave equation from the Lagrangian?

Consider small displacements, $y(x,t)$, of an element of a string (circled in red and shown below) from equilibrium. The force balance in the vertical direction yields: $$+\uparrow \Sigma F: -T\sin(...
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0answers
114 views

stopping, moving of mobile phone when vibrating

A mobile phone move aside when it vibrates. How is that happening ? and most importantly is it possible to make any changes to the vibration motor to stop moving when vibrating or any other methods to ...
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0answers
561 views

Modal analysis with aerodynamic damping

I'm using modal decomposition to predict the steady state response of a beam structure to harmonic loading. The structure itself is very lightly damped, but we know from experiments that the ...
1
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1answer
518 views

Spring Damper System for a Vibrating Motor

Good day people of SE I have a friend that has a final year project and is stuck. He has a motor with a small weight at the end of the shaft that causes vibrations. This motor is on a thin plate. ...
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2answers
455 views

Does the frequency of a vibrating substance like a string depend on its properties or simply depend on the agent which vibrates the string?

We know that if someone vibrates a substance like a string, the string oscillates with its natural frequency. But I think the frequency depends on the rate the agent like a man's hand does vibration ...
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2answers
309 views

Picking up audio using high speed video?

In the movie Eagle Eye, ARIIA (an intelligence-gathering supercomputer/AI) picks up audio using video recording of the vibrations in a coffee cup. How close is this to reality? I have see it done ...
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1answer
351 views

Sound - for purposes of vibration

What is the best way to distribute noise from more than one source (I'm envisioning a system with many), within a dome, with the ground as its primary target, at optimal frequencies and volumes to ...
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1answer
35 views

Vibrational noise for scientific apparatus on a satellite

Say we're running an experiment on a satellite in some earth orbit. For example, maybe we're imaging something with transmission electron microscope or we're catching atoms in ion traps --- really ...
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2answers
4k views

Frequencies of Matter [closed]

Is it theoretically possible for physical solid matter to vibrate at a high enough frequency to become imperceptible to vision and move through other solid matter?
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1answer
495 views

Why do we need hard steel balls to produce an unusual ‘chirping’ sound?

When two hard steel balls, or similar, are brought gently into contact with each other, an unusual ‘chirping’ sound may be produced.why do we need this material or shape to produce that sound?
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1answer
232 views

To what degree does guitar construction affects the vibration of the strings?

There's an old debate going on in the guitar community about how much does wood choice and body shape affect the sound of an electric guitar. No one denies that there's a difference acoustically (how ...
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2answers
1k views

Vibrational anharmonic coupling and noise-induced spontaneous symmetry breaking in a hexagonal finite mechanical lattice

Happy holidays, everyone! The following is part question, part visual gallery, and part classical mechanics problem. Inspired by snow over the weekend I began simulating the vibrations of the ...
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3answers
24k views

Theory behind patterns formed on Chladni plates?

In this video of vibrating Chladni plates we can see small sand particles align themselves into different interesting patterns (also shown in the image below) which correspond to some particular ...
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1answer
2k views

Spring system - 3 DoF system and its properties while changing stiffness

I was given the attached 3 degree of freedom spring system with the purpose of analyzing it. I came up with the following equation of motion and then I ran Matlab to calculate the corresponding ...
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2answers
792 views

Stick and slip motion: mass and spring inside a box model

I am trying to determine a set of differential equation which can describe the motion of a mechanical system as below. Here, at the bottom we have a plate, and a box on top of it. Inside the box, ...
3
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1answer
2k views

Question about the quantization of lattice vibration (phonons)

In my syllabus about solid state physics they state that lattice vibration is quantized, analogous to the harmonic oscillator: $$E = (n+\frac{1}{2})\hbar\omega$$ So the lattice vibration has zero-...
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0answers
68 views

Closed pipe/sound resonance sound type sound coming from mineral processing plant

I work near a very large mineral processing plant which does vibrate our building and there is also a sound/feeling very similar to the closed pipe/sound resonance that is achieved when opening a back ...
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2answers
133 views

Vibrating system at angular frequency in a vibrating system

Can anyone clarify what does mean the angular frequency of a system in case of the vibrating membrane. Angular frequency is measured in radians per second, what does this have with the vertical ...
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0answers
781 views

Buzzing/Vibration in body under power lines [duplicate]

I am hoping someone can please give me an answer. I was at a dog park with my dog and son (hes 12), which is directly under high/loud voltage power lines. I went to brush some dirt of my sons neck ...
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0answers
2k views

Chladni Plate Mathematics

I am a high school student doing an IB Extended Essay investigation concerning the resonant frequencies of Chladni plates of differing materials and sizes. Would someone please explain the definition ...
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0answers
87 views

Modeling Acoustic Lubrication

I thought about posting this question in the Biology StackExchange site but really it is just the application of my question that applies to biology not the core of the question itself. Can anyone ...
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1answer
386 views

Equations of motion of displacement field

We have an action: $$S[\boldsymbol{u}] = \frac{1}{2} \int dt \int d^3x \left\{ \mu (\frac{\partial u_{i}}{\partial t})^{2} - \nu (u_{ii})^{2} - \rho(u_{ij})^{2}\right\} $$ Where $u_{ij} = (\partial_{...
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1answer
1k views

Does the particle vibrate in 3D space? [closed]

As far as I know, particles vibrate with a frequency and wavelength determined by their energy level. Is this vibration in 3D space?
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0answers
67 views

How can this formula be analyzed intuitively?

Given $$ \bar{U}_{vib}(T) = R \sum_{\text{n.m.}} \left( \frac{\theta_{vib, n.m.}}{2} \right) + \frac{\theta_{vib, n.m.} e^{-\theta_{vib, n.m.}/T}}{1-e^{-\theta_{vib, n.m.}/T}} $$ where $\bar{U}_{vib}...
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1answer
233 views

Duhamel formula for propagators

Let $\dot{z} = A(t)z + b(t)$ with $ z(t) \in \mathbb{R}^n$ and $A(t)$ be a linear map from $\mathbb{R}^n \rightarrow \mathbb{R}^n$. A propagator is also a linear map $P(t,s):$ $\mathbb{R}^n \...
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1answer
6k views

Phase shift of resonance [duplicate]

For resonance to occur, is it true that the force lags behind the motion by $\pi/2$? I saw some notes written that the motion lags behind the force by $\pi/2$ which makes no sense to me. As I watched ...
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2answers
5k views

Can a simple pendulum be considered a simple harmonic oscillator?

Is the motion of a simple pendulum, a simple harmonic motion? It stops vibrating after sometime.