Oscillations Definition and 518 Threads

How do BAO help us measure dark energy? thank you for all the help PF members give in the cosmology forum.

Homework Statement The sun experiences a vertical gravitation acceleration of g=-4πGρz, where ρ is the density of the disk of our Galaxy. a) Assuming that d2z/dt2=-kz, express k in terms of ρ and G. b) Find the general expression for z and w=dz/dt as a function of time. c) If the total mass...

Homework Statement A wave has a wavelength of 3.0m; a frequency of 25.0 Hz; and amplitude of 14.0 cm. The wave travels in the positive x-direction and has a value of zero at t=x=0. How many complete oscillations has the wave made at t= 20.0 s and x=4.2 m? A) 3132 B) 1566 C) 498 D) 25 E) 3...

I am having trouble making sense of the frequency of oscillations for a cyclotron. What I don't understand is, if a the voltage difference of the two dees is switched twice ( each time the particles are about to enter them), then why is the frequency of oscillation the same as the frequency at...

I've been reading a article about pulling a fiber (or actually making it thinner until it becomes single mode). As the fiber's diameter decreases, the transmission profile of the light is showing oscillations. The frequancy of these oscillations increases as the fiber is getting pulled. But I...

Homework Statement A mass-spring system with a natural frequency of 3.6 Hz is started in motion with an initial displacement from equilibrium of 6.1 cm and an initial velocity of 0.7 m/s. What is the value of ϕ? (Question aside: Finding the amplitude of the resulting function?) Homework...

Homework Statement A mass-spring system consisting of a mass of 2.9 kg attached to a spring is subject to a frictional force which is both proportional and opposite to the velocity. The mass is displaced from rest and oscillates back and forth with an ever decreasing amplitude. It is found that...

This is a two part question and something I think I should know off the top of my head, but I don't, and I can't find a ready answer to it on at least a cursory search. The first part has to do with defining a frequency of a wave in general. I can sit here and tap out a beat on a drum that...

Homework Statement A 0.500Kg object is undergoing simple harmonic motion at the end of a horizontal spring with force constant k=300N/m. When the object is 0.012m from the equilibrium position, it is observed to have a speed of 0.300m/s. What is: a) The total energy of the object at any point...

Homework Statement Considering just the electron and the muon neutrino, The Free hamiltonian is written in this basis as: H = 1/2 (E + Δ Cos[θ]) |Ve><Ve| + 1/2 Δ Sin[θ] |Vu><Ve| + 1/2 Δ Sin[θ]|Ve><Vu| + 1/2 (E - Δ Cos[θ]) |Vu><Vu| Since H is not diagonal in this basis, they will exhibit...

Homework Statement An object A with mass 3m is suspended from a fixed point O by a spring of constant k. A second object B with mass 2m is in turn suspended from A by an identical spring. The system moves along a vertical axis through O. Find the frequencies of the normal modes, and the...

Homework Statement Using an electron as a point particle of charge −e inside a positively charged sphere of radius R ≈ 10^(−10) m and total charge +e, find the density ρ(r) of the positive charge for which the electron oscillates harmonically about the center of the sphere assuming that the...

Homework Statement With the atomic clock a second is defined as the time it takes for EM radiation to oscillate 9192631770 times, which equals the energy gap between two energy levels of a caesium-133 atom. Note: it's a translation and the term used with the oscillation is "oscillation periods"...

I'm having some trouble understand this correctly, so I was hoping someone could enlighten me a bit :) Okay, so in the early Universe most of the hydrogen and helium was formed, and then kept in equilibrium, and ionized via photons. So we have a plasma of baryonic matter, including dark matter...

Problem: http://i.imgur.com/o8Q1RGZ.png Solution: http://i.imgur.com/IYiXITJ.png To get d2y/dt2+ρgLby/M=0, you have to sum the forces and set them equal to Ma. But what happens to Mg when you sum the forces?

Homework Statement A string of length L, which is clamped at both ends and has a tension T , is pulled aside a distance h at its center and released. a) What is the energy of the subsequent oscillations? b) How often will the shape shown in the figure reappear? (Assume that the tension remains...

Homework Statement Two particles oscillate in simple harmonic motion with amplitude A, about the centre of a common straight line of length 2A. Each particle has a period of 3.3 s, and their phase constants differ by π/9 rad. (Assume the lagging particle starts at +A. Also assume that the...

Why are they important? I've been learning about them quite a bit and have no idea why they are significant. What is the motivation for their discovery, their use, or even their mention in physics for that matter. All I really know is that when you look/have solutions with the same angular...

Homework Statement Given a pendulum with fixed length, at what angle does the pendulum have to be released at in order to not follow the standard formula for frequency? Homework Equations P = 2pi*sqrt(l/g) The Attempt at a Solution I know that this equation holds for "small" angles (theta <...

Homework Statement mass "m" object is located near the origin of the coordinate system. External force was exerted on the object depending on the coordinate by the formula of Fx=-4*sin(3*pi*x). Find the short oscillation period, and the potential energy depending on the coordinate. Homework...

Homework Statement http://imagizer.imageshack.us/v2/275x215q90/661/kIVMcC.png Mathematical pendulum is the part of the oscillating circuit. The system is in a constant uniform magnetic field. Oscillations is small. Find the normal modes of oscilations. Homework Equations ## \begin{cases}...

Hello Why are neutrino oscillations insensitive to Majorana phases? I'm guessing it has something to do with them being factored out the PMNS matrix using a diagonal matrix ... i.e. U_PMNS = U Diag (a1, a2, 1) Is there a point in the oscillation calculation where they always cancel due to a...

Homework Statement A particle of mass ##m## is placed on a smooth table and attached to a fixed point ##O## on the table by a spring with spring constant ##k## and natural length ##l##. (i) Show that the particle can execute circular motion about ##O## with angular velocity ##\omega## provided...

Hi all, I'm in a intro to wave phenomenon class this semester and unfortunately, our textbook is written by the professor and is really not very good at all. So I'm liking for any recommendations on D.E. books that do well with explaining harmonics. Any recommendations would be greatly appreciated!

Homework Statement A small fly of mass 0.29g is caught in a spider's web. The web oscillates predominately with a frequency of 4.4Hz . a) What is the value of the effective spring stiffness constant k for the web? b) At what frequency would you expect the web to oscillate if an...

Homework Statement A particle of mass m moves in 1 dimension along positive x direction.It is acted on by a constant force directed towards origin with magnitude B,and an inverse square law repulsive force with magnitude A/x^2.Find equilibrium position. Homework Equations B+A/x^2=m*a...

Problem from past PGRE: A particle of mass m moves in a one-dimensional potential V(x)=-ax2 + bx4, where a and b are positive constants. The angular frequency of small oscillations about the minima of the potential is equal to: Answer is 2(a/m)1/2. I understand how this is found 'the long...

Is there a resonant frequency of light? I was just wondering because the higher the frequency of light, the higher the energy. Or is there an optimal frequency?

When using Euler's method of integration, applied on a stochastic differential eq. : For example - given d/dt v=−γvΔt+sqrt(ϵ⋅Δt)Γ(t) we loop over v[n+1]=v[n]−γv[n]Δt+sqrt(ϵ⋅Δt)Γn. (where −γv[n] is a force term, can be any force and Γn is some gaussian distributed random variable. ) . Then if...

I'm stucked in a passage of Particle Physics (Martin B., Shaw G.) in page 41 regarding neutrino oscillations. Having defined E_i and E_j as the energies of the eigenstates \nu_i and \nu_j, we have: E_i - E_j = \sqrt{m^2_i - p^2} - \sqrt{m^2_j - p^2} \approx \frac{m^2_i - m^2_j}{2p} It...

Homework Statement what's the frequency of the oscillations of object? Homework Equations The Attempt at a Solution since sin20t = sin wt , so , w=20=2pi f , my f is 20/2pi . the ans given is C . which is wrong?

Homework Statement the turntable is rotating at 36.25 rpm. the simple pendulum is performing SHM at 36.00 prm. how many complete oscillations would the pendulum execute so that both are in phase? Homework Equations The Attempt at a Solution my working is 36prm divided by 0.25 rpm...

Homework Statement the answer is a for this question. but i don't understand how to get the solution. Homework Equations The Attempt at a Solution mg-k(l-a+b)=ma since mg=k(l-a) -kb=ma a=-(k/m)b k/m=a/b so my ans is sqrt root( a/b)

Homework Statement See picture : Homework Equations ##\sum M_{O}=I_{O}\ddot{\theta }## The Attempt at a Solution Consider the free-body diagram associated with an arbitrary positive angular displacement ##\theta##; The moment about point ##O## is given by ##\sum...

Homework Statement i can't understand why curve above is for under dampling and the below curve is increased dampling. can someone explain please? https://www.flickr.com/photos/123101228@N03/14296397365/ Homework Equations The Attempt at a Solution

Hi, I am just trying to understand the connection between these two things. As far as I understand it: BAO - Before decoupling the baryons were in thermal equilibrium with photons and as a result this gave rise to a pressure force. But given in regions of high dark matter density baryons are...

Homework Statement A spring stretches 0.150m when a 0.300kg object is hung from it. The spring is then stretched an additional 0.100m from this equilibrium point and released. A) Calculate the spring constant (k) B) Calculate the amplitude, period of motion T, frequency f and angular...

Hi all! This question concerns flavour changing oscillations. Let's narrow it down to the neutrino case, where we have additionally the violation of lepton numbers. So electron and muon neutrinos naturally follow the relativistic Dirac equation: (p\!\!\!/ + m_e ) \nu_e = 0 and (p\!\!\!/ +...

Hello, I would like some help with the following question. I highly appreciate your help ! A mass falls freely for 2.0 m before it hits a vertical spring. The mass sticks to the spring, and the system begins to oscillate with a period of 2.2 seconds. If you start a stopwatch when the mass...

Homework Statement The figure shows a thin uniform rod of mass M and length 2L that is pivoted without friction about an axis through its midpoint.A horizontal light spring ofspring constant k is attached to the lower end of the rod.The spring is at its equilibrium length when the angleθ...

Consider a spherical star made of N (very large number) particles interacting via gravity.Let the mass of ith particle be mi and position be xi Let ##I= \sum_{i=1}^{N}m_{i}r_{i}##, U be potential energy and K be kinetic energy 1)Show that the virial equation takes the form...

Homework Statement Following a worked example in my book, I have been trying to get a solution for the equation \frac{d^2u}{dt^2} + \frac{k}{m}u = Fcos\omega t The book says that at resonance, i.e. when \omega_0 (the natural frequency) = \omega (the forcing frequency), the term F cos\omega...

Suppose we allow two masses M1 and M2 in a one dimensional diatomic lattice to become equal. what happens to the frequency gap? what about in a monatomic lattice? Knowing that (M1)(A2) + (M2)(A1) = 0

The question is that a mass m of weight mg is attached to a fixed point by a light linear spring of stiffness constant k and natural length a. It is capable of oscillating in a vertical planne. Let θ be the angle of the pendulum wrt to the vertical direction, and r the distance between the mass...

Homework Statement A small ball of radius r performes small oscillations within a hollow cylinder of radius R. What would be the angular frequency of the oscillations given that the rolling is without slipping? The angle between the radius connecting the center of the hollow cylinder to the...

I'm currently doing a report on 'Neutrino Oscillations and mass'. I have spent today just trying to raise my understanding of Neutrinos/leptons and terminology to do with them. I'm still quite confused and still not entirely sure what in particular about a neutrino is oscillating. Is it the...

The example I'm thinking of is a mass spring system. x = Ae^(\gamma/2)t cos(wt +a) + Ccos(wt) If the steady state has been reached, the displacement due to the free oscillations will be negligible, so does that mean that the only force acting on the mass is the driving force, F0cos(wt)...

BOB S had posted this in a now closed thread: https://www.physicsforums.com/showthread.php?t=360072 Regarding this analysis ... https://www.physicsforums.com/attachment.php?attachmentid=20126&d=1250393723 My questions ... Q1) Does this oscillation from the L-C circuit actually...

Homework Statement A rod of length L is attached to a ball of radius L/6 A spring is attached to a wall, and to the vertical rod 1/3 down the top (opposite the ball). THe rod is displaced a small theta, and released. Find period of oscillation. Homework Equations T = 2pi...

Homework Statement A particle is simultaneously subjected to three SHM, all of the same frequency, and in the x direction. If the amplitudes are 0.25, 0.20, 0.15mm, respectively, and the phase difference between the 1st and 2nd is 45 degrees, and between the 2nd and 3rd is 30 degrees, find the...