Vibrations Definition and 216 Threads

Homework Statement Homework Equations T = 2π√(m/k) mx'' + kx = 0 F = ma The Attempt at a Solution I don't honestly know where to start with this. I'm really out of my league in this class, and I'm trying my best to catch up with the things I didn't quite master in Dynamics and Physics... As...

In a passage of our book (Krane page 141) they add two quadrupole phonons to a ##0^+## state. So as I understand it these phonon can be written in the form ##Y_{\lambda \mu}## with ##\lambda=2##. It makes sense that this corresponds to two units of angular momenta. Then they talk about the...

This isn't really a homework question, just a question i got wrong on test and want to understand: If the tension of a string increases how would the following be affected (Increase, decrease, stay the same, not enough info)? 1. The fundamental frequency of vibrations on a string? 2. The...

Homework Statement I have to determine the frequencies of the normal modes of oscillation for the system I've uploaded.Homework Equations [/B] I determined the following differential equations for the coupled system: \ddot{x_A}+2(\omega_0^2+\tilde{\omega_0}^2)x_A-\omega_0^2x_B = 0...

Vibrations are everywhere and the question is if there is some fundamental reason for this. Per example, symmetries and the least action principle are behind the conservation laws. What is the reason that vibrations are so common?

Hello, I have to hold a short course on applied mechanics and mechanical vibrations and I would like to develop a tool similar to the one shown in the linked webinar below (min 27.43): https://www.youtube.com/watch?v=0TH5SLghYPY&t=27m45s What do you think would be the best software to develop...

Homework Statement A violin string is vibrating at a frequency of 880Hz. How many vibrations does it make when the sound produced travels 332m through air at temperature of 0 degrees Celsius. Homework Equations Not sure. The Attempt at a Solution I'm not quite sure how to solve this equation.

Hi there, I'm studying for an exam in mechanical vibrations, and I'm at the moment looking at longitudinal waves in continuous beams - and I've run into some problems. The whole idea is to explain the solutions of the system in terms of eigenvalues and eigenfunctions, which is not that big of...

In IR spectroscopy, bonds vibrate and therefore there are moving charges and usually a changing dipole. If accelerating charges cause EM waves to be given off due to the changing electric field then shouldn't the vibrating bond be constantly emitting photons and therefore losing energy in a...

so my group was given this topic to discuss in physics. What are some sub topics that i can talk about? i don't know where to start my research example: 1) how a violin makes sounds? - - 2) _____

Why is sound produced? Say, for example, when a stone hits a tin box a sound is produced. Why is this sound produced? Even if the sound is produced in the ear, we generally say that the vibrations of the ear drum produces the sound, why is it produced. Why does vibrations produce sound. Even a...

So I just poured water in a glass to clench my thirst. Hit the 2/3 empty glass with a pen and a high frequency started resonating for a brief moment, which I percepted as sound. When I tilted the glass the tilt resulted in change of frequency. When the glass was empty there was no change in...

Hello guys, this question showed up in my test last week as a challenge question, but the problem is, I'm the first year at college and have not yet learned to solve differential equations. Of course I did not manage to do it but I´m pretty eager to learn. Thanks in advance

Homework Statement The amplitude of vibration of a mass on a horizontal spring experiencing SHM is = 0.13m. The mass is 85g and the force constant is 55N/m. a) What is the maximum elastic potential energy of the system. b) Find the speed of the mass when it's position is x = 7.4cm from the...

The book is expensive, so I want a book like Bekefi's and Barrett's Electromagnetic Vibrations,Waves,Radiation. Preferably at a higher level than this book. Thank you!

I'm creating something as a side-project, but I've encountered a problem in a field I'm not well-versed in. There is a material I am looking to excite with a resonance frequency of 50 Hz. I need the smallest possible device to create the largest amount of vibration, I've looked into some small...

Hi everyone! It's my first time working with vibrations (and on this site) and I'd like to know what the best device is for simulating a car engine's vibrations is. Basically I want to generate a random range of frequencies. I would like to keep it as small and for it to use as little power as...

I've been researching this subject for a little while. I'd like to hear your ideas, because the topic is widely discussed. So here is some part of my research which makes my opinion quite clear: "Sometimes we say , that one is moved by music. Of course, it does not mean for him/her to be...

Homework Statement Please see attached. Part ii) Homework EquationsThe Attempt at a Solution So I try to conserve volume as it suggests in the hint. I take the initial volume of the region to be given by: $$ h \times \delta x \times l = (\delta x + \eta) (h+\Psi) l $$ Where l is just some...

Homework Statement A spring is attached to the ceiling, a pulley is attached to the other end of the spring, a string is suspended over the pulley, and a mass attached to the free end of this string. The system oscillates vertically. Can someone PLEASE help me derive this equation for natural...

Homework Statement Derive Newton's and Lagrange's equation of motion for the system. Discuss differences and show how Newton's equations can be reduced to lagrange's equations. Assume arbitrarily large θ. The system is a pendulum consisting of a massless rod of length L with a mass m...

Homework Statement I am currently taking mechanical vibration course and am given coursework. A wooden block (20X200mm) floats half submerged in water. Determine the frequency of small oscillations of the block rolling from side to side. In this motion, the centre of mass remains in the plane...

I know there is a previous post here about this, but it didn't seem to cover the angle I am getting at... I understand sound to be vibrations that travel through a medium such as air or water. However, what actually generates these vibrations? For example, hitting a piece of steel with a rod...

Hi, my teacher is pretty bad at teaching, my book offers problems with no solutions and poor examples, and there is no solutions for the problems on the internets. Does anyone know a manual/pdf/website where I can find problems and solutions for waves and oscillations? I have read the book and...

Hi, I was wondering if someone can explain to me the following. If I have a vibrating molecule in a solution, what effect would this vibration have on other particles in my solution which are different. Can the vibration be the same for them if they are not excited (do not vibrate due to...

Recently I created a structural vibrations simulation and would like to hear some feedback or suggestions.

I know this question has already been asked, but the given answer di not help me. Hopefully someone can post their full solution? A piston of mass 4.53(kg) is traveling in a tube with a velocity of 15.24(m/s). It engages a spring of stiffness 350 (N/cm) and a damper with a coefficient of 1.75...

Homework Statement I have a system of five coupled ODEs. I believe I should be able to reduce it down to four coupled ODEs, but I am not sure how. This system is modeling a quad X rotor where the arms are viewed as end loaded cantilever beams with motors attached. Homework EquationsThe...

Hi everyone, I'm having a bit of difficulty choosing an admissible function for a fixed-fixed nonuniform bar. I chose the function φ(x) = 1 - cos(2πx/L). But when solving for the the stiffness and mass coefficients: kij = ∫EA(x)φiφjdx mij = ∫ρ(x)φiφjdx, I am not sure where I should have...

Hello, As of this moment I am trying to get in the process of writing an Extended Essay on Chladni Plates, more specifically on a circular vibrating membrane with free ends. To begin with I thought the concept could be simplified to such an extent where I could take a cross-section of the plate...

Hello I am making a vibration project which requires me to mount eccentric weights on both sides of an electric motor. I must submit the "generated force(in Kg)" by this motor.The RPM of motor = 1000 Total weight on both sides of the motor = 16.8Kg (8.4Kg on both sides) The radius(distance from...

Hello fellow PF members, I'm currently in my senior year in Mechanical Engineering at Oregon State University. I'm considering going on to get my Master's Degree to gain more knowledge (since I'm fascinating by them). I really like Math and have a Math Minor already. I am looking to go into a...

I've been researching on Damped Oscillation (in vibrations) for a few days for a research paper, however I couldn't find any applications. I would be very thankful if anyone can tell me about its applications.

Does both space & time vibrate when objects move or when they vibrate when objects accelerate? So, what happens of these vibrations? How are they converted back into matter to maintain a cycle?Do these vibrations affect the motion of other moving objects (although negligible)?

I am struggling with the following question, it is a mixed (lever and linear) 2DOF vibration problem, something I never came across before. I am afraid I am missing something on the FBD, thus the differential equations of motions are wrong. Homework Statement Homework Equations...

We measure time based off of atomic vibrations, so time dilation from gravity and velocity are nothing more than pressure applied to the atoms, slowing their vibrations. This isn't an accurate measure of what we consider time, but more of a measure of the reaction of atomic vibrations under...

can i locate region in an automotive, which is safe from vibrations, by modal analysis? can i conclude that blue region in mode shape a safe region?

Hello, as we all know, in compound solids atoms are always vibrating with some degree, depending on the temperature or the average kinetic energy they posses. My question is how do compound objects maintain their rigidity in those conditions, or to say it better how do atoms stay in fixed...

Homework Statement https://ia701205.us.archive.org/11/items/Mechanics_541/LandauLifshitz-Mechanics.pdf Page 72 of the book itself, but Page 81 of the PDF. Problem 1. Homework Equations See Section 24 of the book. The Attempt at a Solution So far I have completed and...

I am trying to work though an example on this topic in my book and have reached a point that I am not sure about. I was wondering if anyone could help me clear this up. The equation of motion for a spring-mass system with no damping and a periodic external force is mu'' + ku = Fcos\omega t...

Is it possible to have a body supported by truss linkages and isolate them from any stresses and impulses? Say, we are supporting a platform on the top of a set of rigid, pin jointed and cross-linked members. If small impulses act on the bottom on the linkages(upwards), is there any...

Homework Statement $$ M \frac{d^2x}{dt^2} + c\frac{dx}{dt} + kx = F_{0}cos \omega t $$The Attempt at a Solution $$x(t) = asin\omega t + bcos \omega t $$ $$ a = \frac{\omega c F_{0}}{(k-\omega^2M)^2 + \omega^2c^2} $$ $$ b = \frac{(k-\omega^2M)F_{0}}{(k-\omega^2M)^2 + \omega^2c^2} $$ $$ x_{0}(t)...

Hi all, a) Do a proton still vibrate if it isn't bound to its nucleus? I mean, if it is "alone" (no neutron, no electron). Do anybody know if they have done experiments on it? I would like to know if it has been observed/measured in some way. b) An electron does not "like" to be still, it...

Homework Statement Find the period of low-amplitude vertical vibrations of the system shown. The mass of the block is m. The pulley hangs from the ceiling on a spring with a force constant k. The block hangs from an ideal string...

hi! i'm beginner in the subject of vibrations. i'm trying to understand the waterfall plots. i have attached a waterfall plot. can someone please help me to understand it? waterfall plots are used when the operating speeds are varying (run up or coast down). in this plot, as the...

We have common detectors for radio, microwaves, visible, ultraviolet, xray and gammy rays.. but how about the infrared frequencies from molecular vibrations. The frequencies of molecular vibrations range from less than 10^12 to approximately 10^14 Hz. These frequencies correspond to radiation...

Homework Statement We are deriving the PDE that models a hanging chain of Length L. The x-axis is placed vertically. Positive direction points upwards. The fixed end of the chain is at x=L. Let u(x,t) denote the deflection of the chain. We assume the deflection is in the x,u plane. Let...

Here is my problem verbatim. A mass weighing 100g stretches a spring 5cm. If the mass is set in motion from its equilibrium position with a downward velocity of 10cm/s, and if there is no damping, determine the position \(u\) of the mass at any time \(t\). When does the mass first return to its...

The title may be incorrect, I named this after the section of my book in which this is located. My problem is as follows. Determine \(\omega_0\), R, and \(\delta\) so as to write the given expression in the form \(u=R\cos(\omega_0 t-\delta)\) \(\color{blue}{u=4\cos(3t)-2\sin(3t)},~\text{My...

Homework Statement A mass of 0.3kg is suspended from a spring of stiffness 200Nm-1. If the mass is displaced by 10mm from its equalibrium position and released, for the resulting vibration calculate: The maximum velocity of the mass during the vibration. Homework Equations v =...