Vibration Definition and 429 Threads

Homework Statement A body of arbitrary shape has a mass m, mass center at G with a distance of D and a radius of gyration about G of K. It is hanging, and pinned at the top. If it is displaced a slight amount of angle P from it's equilibrium position and released, determine the natural period...

Hi all, I am confused with the amplitude at 1x, 2x, 3x frequency. The 1x, 2x and 3x is the harmonic (or mutiples) of the original frequency, meaning that if the shaft is turning at 1500rpm, then 2x will be the amplitude at 3000rpm and 3x will be the amplitude at 4500rpm right? But how will...

Homework Statement the problem is in the attached file, I am having trouble with part d and e. cheers. [the answer for B is mr^2(0.5-16/9pi^2)] Homework Equations The Attempt at a Solution i won't upload all my working as i have stuff everywhere but for part d: i got my...

Im new here and I am not an engineer but i have a question hopefully someone can offer their thoughts on.. I film and record bands live and i want to run a video camera at concerts that are often very loud.. At times I also need to position the camera in front of the PA speakers and this...

Hi looking for some help on the below I'm a little bit stuck. The effect of an earthquake on an elevated water tank is to be investigated. The water tank has mass m=2x10^6 kg and natural frequency wn=10.6 rad/s and a damping coefficient of 12% critical damping. Ground acceleration can be...

1. Homework Statement a mass attached to the lower end of a vertical spring causes the spring to extend by 25mm to its equilibrium position. The mass is then displaced a further 20mm and released. a trace of the vibration and time mesurements are taken. From these mesurements it can be seen...

Homework Statement I'm using Eugene Hecht's 4th edition of Optics, doing problems from chapter 8 on polarization. Write an expression for a polarization-state lightwave of angular frequency (omega) and amplitude E propagating along the x-axis with its plane of vibration at an angle of 25...

Homework Statement I've been given this as a piece of coursework and I'm having a bit of trouble starting it. I know most of what I need to do once I can figure out how to calculate a few basic (though essential) values. The first part to the question is as follows: [SIZE="4"]"Determine...

Hello, I am new in computational chemistry. I was calculating by "Moller Plesset Second Order perturbation theory -MP2-" (using GAMESS) molecular parameters of Cs3Cl2-. Among them i found two complex frequencies of vibration. My question is now, what is the physical meaning of those complex...

say a system has 3 modes. under free vibration does it vibrate in all the modes all just one mode? why. also if we apply a either a impulse or pulsating force to the system, in which modes the system is going to vibrate and why? thanks.

Hi! I am new. Please call me Kaffe. I am a theologian of the Extraterrestrial Presence and my studies have led me to Physics and the Science of Frequency and Vibration. I have been thinking about developing a project over the summer to see if I can get an object to hover using intense shock...

I'm wondering about what's going on in an effect I've noticed with heating pads (as well as electric mattress pads). Try this experiment: take an ordinary heating pad (one of those flat rectangular things about 1 foot by 1.3 feet with an electric plug), plug it in, and have a friend sit...

hi guyz, I have Turbiine(5500RPM)-Gearbox(output 1500RM)-Generator-Exciter-Permanent Magnetiic Generator(PMG). I have problem with high axial vibration at ball bearing permanent magnetic generator. Axial vibration at 5500RPM, but it rotate at 1500RPM. This overall is 3-5 times radial...

Hello Every one, When I am looking at the design of a vibration screen, I found that the claims from different source have different equation. Please have a look on the attachment. You can see "Claim 2 " is a more general approach but need to know spring constant k. while "Claim 1"...

I roughly understand that when we hit a metal rod right into the end will excite longitudinal vibration in the metal rod, and the place we hold will be a node. the position i hold will kind of determine the frequecy of the ringing sound produced. Is that right? But what will happen if we hit...

Pls help me to solve this..

I designed a spring and mass system (damping unknown) that is vibrated by applying a sinusoidal force to the mass using an electrodynamic shaker. The mass is estimated to be 100 Kg. The spring is actually 4 springs, each with a k value of 63.55 N/mm, supporting a platform (one spring at each...

Does anyone have a graphic example of underdamped vibration?

Does anyone have a graphic example of beat vibration?

I posed this thought experiment elsewhere, so the tone may seem a bit odd. It's based on what I've been reading on physical chemistry, atmospheric radiation and thermal physics. Just wondering if my interpretation is on the money or if I've made any incorrect assumptions. "Time for another...

I understand that CO2 molecules absorb infrared at 2.7, 4.3 and 15 microns, this makes them become vibrationally excited (rocking, stretching, bending, I don't know all the modes). I have a few questions from this point: 1. When the CO2 molecule re-emits that energy is it obliged to do so...

How does this tiny generator work? http://www.engadget.com/2007/07/06/tiny-generator-turns-vibrations-into-electricity/

Mechanical ad Electrical vibration EASY question please help? In Boyce and Diprima textbook it says that: mu'' + ku = 0 . Then it says the general solution of this is: u = Acos (w^2)t + B sin (w^2)t , where w^2 = k/m It provides no explanation how it arrives at this. Where does...

Homework Statement I am asked to provide an anti vibrational support mount for equipment mounted on turbo-prop aircraft. The equipment has a mass of 40kg. the vibrational response of the equipment to the environmental disturbances will need ot satisfy a safety limit prescribed by the...

1. A mass attached to the lower end of a vertical spring causes the spring to extend 25mm to its equilibrium position. The mass is then displaced a further 20mm and released. A trace of the vibration and time measurements are taken. From these measurements it can be seen that the displacement...

Homework Statement The solution to the Initial value problem, x''+2x'+5x=0, is the sum of the steady periodic solution x_sp and x_tr. Find both. Homework Equations The Attempt at a Solution I already found x_sp ( the particular solution). It is (-44/533)cos(7t)+(14/533)sin(7t). r^2+2r+5=0...

need a tutorial on how to model piezometric material in ansys.. i am working on a project related to piezometric control of vibration..please need it very urgently!

When we have vibration excitation then the radius of nucleus is define like: R=R_0[1+\sum^{\infty}_{\lambda=0}\sum^{\lambda}_{\mu=-\lambda}\alpha_{\lambda\mu}Y^{\lambda}_{\mu}(\theta,\phi)] where \alpha_{\lambda,\mu}=\alpha_{\lambda,-\mu} and \alpha_{\lambda,\mu}=\alpha_{\lambda,\mu}(t)...

If the light move from left to right, what's the vibration direction of light wave? up-down or front-back or some other ways?

Hi.. I'm trying to do the damped vibration analysis of a cantilevered beam. Although i am choosing no damping in subdomain settings menu, it solves the problem as if the material is damped (the result is a damped vibration signal). Is this is a bug or am i missing something? Thanks in advance

Hello MechEs (or anybody else who'd care to reply) I'm about to get a small, but fairly sensitive analytical scale recently (down to 0.01 mg) and now I'm trying to figure out a way to dampen ambient vibration from the room and its surroundings (people walking around, HVAC, etc.) I've got a...

1.A 2-meter long wire vibrates with a frequency of 330 Hz when the tension is 500 N. What is the new frequency if the tension on the wire is doubled? i have no idea how to solve this,, help..

Hi all, I have a question, I am trying to do to measure the stress on human feet while standing on a vibrating platform. The platform was placed on top of a cam and the cam was driven by a motor. I know most of the parameter, i.e. frequency, speed, acceleration but how can i calculate the...

hi all.. How can i describe initial conditions or initial forces in comsol(like wave forms such as ramp or parabolic)? I couldn't find it in the manual. in ansys, i do it in time steps(in solution options).(like t=0, F=10 t=0.001 F=0) I tried to give initial displacements to the points but...

Homework Statement The slender rod AB of weight W_{AB} is attached to two identical collars, each of weight W. The system lies in a horizontal plane and is in equilibrium in the position shown when the collar A is given a small displacement and released. Calculate and plot the period of...

Homework Statement Determine the max and min values of x and their times from 0 to 2s initial conditions X0 = 0, V0 = 1m/s http://img266.imageshack.us/img266/2198/figure1.jpg Homework Equations Undamped force vibration: m\ddot{x}+kx = F0sin\omegat Damped force vibration: x =...

How fast does an atom vibrate in m/s. I have found how fast it vibrates in hz but I'm trying to convert that to speed. Thanx.

1. SDOF Systems Governing Equation m(dx^2/dt^2) + c(dx/dt)+ kx = F(t) how do i get this equation below? Free Critically damped Vibration x(t) = e^(wt) [x(0)(1+wt) + (dx/dt)(0) t] (dx/dt is x with 1 dash on top)

Homework Statement A child on a playground swings through a total of 42 degrees. If the displacement is equal on each side of the equilibrium position, what is the amplitude of this vibration? (Disregard frictional forces acting on the swing) The Attempt at a Solution I know amplitude is the...

an astronaut in space sits on a chair that vibrates horizontally at the end of a spring. the spring has a 1200-N/m spring constant, the amplitude of vibration is 0.50 m and the speed of the chair as it passes through equilibrium is 2.0 m/s. also devise another method to determine the mass, you...

Hey, so I just ripped the two permanent magnets out of an old seagate hard drive, and have a breadboard for my electronics class to practice with logic chips, and figured id wrap some wire around one of the magnets and see what happens. I got around 10 turns of the wire about the magnet, and...

so u = -cos(t) + sqrt(3)sin(t) so the Wo = 1, and R =2, but how do i find delta? tan(del) = sqrt(3)/-1, but the answer has it as u = 2cos(t-2pi/3) i can't get the 2pi/3 no matter what i do... thanks

if we have a machine is running at 6,000 rpm. It is vibrating at 1 mil Pk-Pk. Calculate the velocity & acceleration of the vibration in mm/s & mm/S2. Explain the calculation. can anybody provide me the formulas?

Hi, I have a simple question to ask: What is the Eigenfrequency mean in vibration? I am confused and can anyone here explain to me or provide me some useful link? I am trying to use comsol to analyse the vibration frequency from a plate, which was mount on top of 4 camshafts. These...

Hi, Can anyone recommend a text for Vibration. My university recommends Mechanical Vibrations by S.S Rao but it has received bad reviews. I am an undergraduate in my second year and prefer the sound of a book that makes this less complicated...? Thanks Will

Hi, Suppose we have a fixed-fixed beam with a distributed force acted in between -on a part of the beam. I have found out the fundamental mode of vibration i.e calculated the fundamental resonant frequency of the above case. But there will be higher order mechanical modes too.. In case...

Hi.. I have a question about natural fvibration. Every object has natural frequency and modes of vibration. Let us consider a simple cantilever beam for our discussion. and Let's say its first 4 modes of vibration are at 3, 6, 10 and 20 kHz respectively. (I made up these frequency values)...

Hi All, I need some basic info of He closed cycle cryos..(like working principle, etc).. I have a compressor, which compress He gas and passed into a cryo's coldhead. So He gas expands in side the coldhead and cools the coldhead..then it again passes into compressor..so the cycle repeats.. I...

[b]1. When seven people whose average mass is 83 kg sit down in a car they find that the car drops down 0.87cm lower on its springs. Then they get out of the car and bounce it up and down. The acceleration of gravity os 9.8m/s^2. What is the frequency of the car's vibration if its mass (empty)...

A string of length 0.29 m is fixed at both ends. The string is plucked and a standing wave is set up that is vibrating at its second harmonic. The traveling waves that make up the standing wave have a speed of 115 m/s. What is the frequency of vibration? fn=n(v/2L) I tried...