Questions tagged [vibrations]

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16 views

Determination of a phase shift function using wave equation

I have a question about solving for a phase-shift function. Suppose the function $$y(x,t) = A\cos(\omega t+\phi(x))$$ obeys/satisfies the wave equation $$\frac{\partial^{2}y}{\partial t^{2}} = c^{2}\...
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Obtaining damping $c$ and spring $k$ with a $F(x)$ and $E(x)$ curve

I'm having a hard time finding c and k of a suspension system, having at my disposal three curves: F(x), Energy(x), Energy(F). Is it possible to find them with just the three curves?
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22 views

Lumped mass model of rotating engine crankshaft [closed]

My objective is to model a rotating crankshaft as a lumped mass model. This way, I can predict the stress at points along the crankshaft, using as input the force acting on each piston as well as some ...
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38 views

When using $\Delta \omega/\omega _{0}$ as a measure of how sharp a resonance is, why divide by $\omega_0$?

In A.P. French's Vibrations and Waves, page $111$, the author said the following about the sharpness of a given resonance, We can say that the resonance is narrow if the width is only a small ...
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1answer
32 views

Clothing fibres which would prevent the (vibration / resonance) effect live music has on the body

My 12 yr old cannot bear live music concerts. The bass, i think, hurts her entire body. She tells me she cant breathe, & the pain is a stab sensation in her chest & abdomen. Shes a very lean &...
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1answer
161 views

Eigenfrequencies of an elastic bar with viscous damping

I want to know the mode shapes and associated eigenfrequencies and damping ratios of a bar that vibrates in a longitudinal direction and has linear elastic as well as viscous material properties. ...
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1answer
30 views

Physics behind hissing sound when opening something that is vacuum sealed?

I am aware that it is the differences in pressure, and gases rushing into the container that makes the sound occur. But, what exactly is responsible for making the audible hiss sound when this ...
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1answer
62 views

Why things in motion make noise?

In most of the cases on earth,the things in motion definitely make noise but things at rest do not.For example:-boiling water,a body falling down,a man walking on road,flowing water etc. But the ...
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1answer
112 views

Has any scientist actually seen a $H_2O$ molecule vibrate?

Has any scientist experimentally confirmed that H2O molecules vibrate when heat energy is provided to them? Maybe by passing X-Rays through them or by some special camera...?
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6 views

Symmetrical design of a tuning fork [duplicate]

I was reading Ch. 10 of Kleppner and Kolenkow and I came across an explanation which said "The energy loss in a tuning fork is primarily due to heating of the metal. Air friction and energy loss to ...
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1answer
37 views

How to understand motion of waves through functions of two variables - time and distance? [closed]

$$ s(x,t)= A \sin(\frac{2\pi}{T}t-\frac{2\pi}{\lambda}x) $$ Basically I would love to get some plausible and thorough explanation of plotting these two independent variables in order to satisfy the ...
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1answer
41 views

When a skyscraper sways in the wind, in which direction is the motion?

Skyscrapers sway in the wind (Source here). Which direction, relative to the wind, do they sway, ignoring effects of other buildings nearby? I can imagine wind from the North blowing a skyscraper's ...
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24 views

Vibrations in a cup of water

I realised that when a normal ceramic cup is placed on a table, and the table is knocked repeatedly, there seems to be a single focal point where there are circular waves on the inside of the cup ...
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15 views

Relation between output voltage and pressure field from a piezo

When applying a sinusoidal voltage with an amplitude $V_{pp}$ and a frequency $f$ across a piezoceramic transducer, the piezo vibrates and generates pressure fields. Is there a formula for the ...
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1answer
36 views

'Drummy' sound when striking with a hammer

In building there is a common test for masonsry structures that involves striking the structure with a hammer and listening to the resulting sound. If the sound is ringing the structure is fine but if ...
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1answer
23 views

The vibration of mechanical ondes

i want to ask about the relation highlighted in yellow in the picture the equation of motion of this system can be obtained using the Lagrange formalism, but my question is about this relation i have ...
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1answer
71 views

Do string instruments really create standing waves or not?

I have seen similar questions regarding this but containing answers that somewhat disagree with each other which makes it hard for me to understand this. My question is mainly about when plucking a ...
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18 views

Energy in a vibrating part of an engine

I have sensor data of the vibrations of the parts of an engine. I was wondering whether I could calculate how much energy a part contains in a given time window. Now the energy of a wave given by ...
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30 views

How does vibration transform after rotation of the vibrating object?

I can't find the math of that. Imagine a vibrating object, like a circular membrane, with vibration modes $\phi_{ij}(x,y)$. Let's express the initial vibration state like $u(x,y,t)=\sum_{ij}a_{ij}e^...
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1answer
52 views

Different energy levels in quantum mechanics

I have a doubt regarding energy levels. I saw that translational energy levels are quasi-continuous, rotational energy levels are discrete and vibrational energy levels are more discrete. I want to ...
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3answers
464 views

Vibration on the guitar when playing two strings

I know that when I am playing one string on the guitar, it creates a standing wave which causes the entire body vibrates in its frequency and therefore create sound waves. But, what about two strings? ...
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1answer
13 views

For vibrations in continuous beam, what is the unit of eigenvalue?

I have been solving a fourth order euler bernoulli differential equation to solve for vibrations of a continuous cantilever beam. When I verified for them using Comsol eigenvalue solver, it gives me ...
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2answers
79 views

Difference between sound and high temperature [duplicate]

Though vibration is a common concept in sound and “high temperature”, the essential difference between the two is mentioned to be the way the vibration takes place. The former has vibrations that ...
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2answers
711 views

Difference between Oscillatory motion and vibratory motion

What is the difference between oscillatory motion and vibratory motion. I have read in my book that "If the amplitude of oscillatory motion is extremely small,the motion is called vibratory motion". ...
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1answer
82 views

Frequency of longitudinal waves on a string

I recently heard the composer Ellen Fullman on her Long String Instrument, which consists of steel wires of approx. 20 m length played by rubbing/stroking the string longitudinally. Changing the ...
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1answer
48 views

Damped forced Oscillation with variable external frequency

Consider that we have the following forced vibration with an input frequency $ω(t)$ variable in time. $$m\ddot{x}+c\dot{x}+kx = F_0 \sin{(\omega(t) t)}$$ Assuming that the solution must be a ...
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30 views

Spring oscillation model

When a spring - in real world - is extended $Xo$ from its natural position, it oscillates and eventually decreasing it's amplitude with time, comes to a stop. Is this a damped system or no? If yes how ...
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36 views

Coupled Harmonic Oscillator (Forced Vibration)

I derived two equations for a 2DOF harmonic oscillator system, declared state variable equations, and placed them into matrix form: $Ax' + Bx = C$. I have a Matlab script to determine the constants ($...
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3answers
393 views

Why choosing for prime numbers eliminates vibration?

I have read that the spokes of a car wheel are usually five because, besides other substantial reasons, five being a prime number helps to reduce vibrations. The same also happens with the numbers of ...
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1answer
29 views

Producing harmonics of standing wave on a string at non-coprime divisions

I am currently researching the properties of producing harmonics on a vibrating string fixed at its ends (e.g. violin). Lightly touching a node at division of the string a/b will sound harmonic b iff ...
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32 views

At what rate is tension released from a plucked string (eg. guitar string)?

Tension in a plucked string (such as a guitar) dictates many of the important changes that occur in the sound of the string over time. eg. It causes a pitch bend, a change in inharmonicity, and ...
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2answers
144 views

A hypothesis based on the principle of conservation of momentum

When a ball hits a wall (ground), some quantity of its momentum must be transferred to the wall at rest. If else the ball would bounce back with the exact same speed as it did when it collided with ...
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1answer
70 views

Vibrations in Stones and Crystals [closed]

I have read studies done that indicate certain sounds can either disrupt or reinforce the molecular structure (I think this is the terminology used) of living organisms. This is based on the idea that ...
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1answer
111 views

Difference in Sound and Heat

What makes sound and heat distinct ? The answer is said to lie in the fact that the former consists of vibration in an ordered fashion while the latter is not. But why would ordered vibration not be ...
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2answers
121 views

Can mass be ejected from a black hole within the Schwarzschild radius?

This goes far beyond my limited knowledge regarding the physics of black holes, but my colleague told me this today: I doubt that if I stand on the surface of a black hole - inside the ...
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1answer
122 views

Can dispersion relations be derived using Euler-Lagrange equations?

The question is long because of the demonstrations I give, but the problem is simple, so bear with me for a minute. I am trying to derive the dispersion relation of a semi-infinite system using Euler-...
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44 views

Transverse vibration of triatomic molecule from Landau Mechanics Sec. 24

Transverse vibration of a triatomic molecule ABA which consists of two identical atom A and one another atom B such as $\mathrm{CO}_2$ is depicted in page 24 Sec. 24 Landau Mechanics. The ...
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1answer
103 views

What are “vibrations” in a field in Quantum Field Theory (QFT)?

For example, in a 2013 article for NOVA Don Lincoln writes: Everywhere in the universe there is a field called the electron field. A physical electron isn’t the field, but rather a localized ...
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17 views

Does putting a part under stress change its natural frequency?

It is easy to imagine how tension changes the natural frequency of a wire. Intuitively it happens with a guitar string when you bend the neck. However, does putting a beam under stress (internal or ...
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19 views

Will a cantilever tube vibrate if fluid enters from its free end and flows into the fixed end?

For dynamics of a cantilever pipe with fluid flowing from fixed end towards free end, there are values of frequency for a threshold of flow velocity that gives unstable, stable and neutral systems, ...
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1answer
47 views

How to measure the mechanical vibration when a hammer hits a nail? [closed]

I want to know the exact location of the vibration sensor that can be placed to measure the vibrations created by a hammer hits the nail.
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21 views

Normal mode decomposition of a triangular hexagonal lattice

I was trying to understand and redo the methods used in a previous question: Vibrational anharmonic coupling and noise-induced spontaneous symmetry breaking in a hexagonal finite mechanical lattice ...
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28 views

Physics of a catenary with sinusoidal motion at one end

If we have a catenary line with a mass per unit length of m with one end fixed and the other end moving in sinusoidal motion like $A.sin(\omega.t)$, how would I ...
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2answers
131 views

Which waves are produced during tuning fork vibration? [duplicate]

In my book, it is written that transverse waves are produced during physical motion of tuning fork. But vibration of tuning fork produces sound which are compressional in nature . Please tell me ...
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26 views

vibration and movement of electric appliance

So, what I am thinking about here is a cooking mixer placed into a bowl which is turned on and left moving on its own. The bowl is such that it does not topple nor the mixer falls out of it. Once the ...
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29 views

Book for electromagnetic waves and radiation

MIT course 8.03SC recommends Electromagnetic Vibrations Waves and Radiation (The MIT Press) by Bekefi and Barrett for extra reading however I am unable to find any soft copy online and its too costly ...
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1answer
70 views

Why are higher frequencies amplified less by filling a bottle with warmer water instead of colder water?

Out of curiosity I was trying to figure out what makes the sound of hot water versus cold water filling a bottle different, but I'm unable to find any explanation as to why such differences occur. ...
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2answers
66 views

The Strings have a finite size they can vibrate?

as I searched about the Strings theory I found out this explanation: Since the strings have a finite size they can vibrate. All the known particles of nature are just different modes of vibration of ...
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2answers
62 views

What makes quartz oscillators vibrate?

I understand that the principle behind it is piezoelectricity and electrostriction (inverse piezoelectricity), but how does one make the crystal vibrate? The only thing I can think of is using an ...
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5answers
298 views

What is the reason behind resonance?

At the technical highschool that I attend, the instructor said that the cause of resonance is that energies increase differently. Kinetic energy increases quadratically and potential linearly, so the ...