Harmonic Definition and 1000 Threads

  1. F

    How to find phi in simple harmonic motion

    Given a position vs time graph of simple harmonic motion of an object and using the equation x(t) = xo = A sin (ωt +Φ), how am I supposed to find Φ? I can easily find A and the period (T). I also know T = 2 pi / ω, so I can find ω. But I don't know x(t) and t. I tried finding random points in...
  2. ZARATHUSTRA

    Understanding the Equation of Motion for Simple Harmonic Motion

    For one-dimensional simple harmonic motion, the equation of motion, which is a second-order linear ordinary differential equation with constant coefficients, could be obtained by means of Newton's second law and Hooke's law and i don't get this part which...
  3. pyman999

    Simple harmonic motion acceleration

    Homework Statement Homework Equations acceleration = -(2*pi*f)^2 * x, where f is the frequency and x is the displacement from equilibrium. The Attempt at a Solution I thought the acceleration would be greatest when the displacement from equilibrium is greatest, so at point P, but the answer...
  4. pyman999

    Simple harmonic motion question

    Homework Statement http://puu.sh/cAjmp/14ba3df23a.jpg Homework Equations Acceleration at any instant: -(2*pi*f)^2 * x, where x is displacement from equilibrium and f is frequency. The Attempt at a Solution Firstly, I know it can't be D as acceleration would increase as potential energy...
  5. L

    Second-Order Harmonic Motion Equation: Solve as 2 linear diff eqs

    Homework Statement [/B] Write the second-order equation for the harmonic oscillator, y ̈ + ω2y = 0 as two linear ordinary differential equations. What is the analytic solution y(t) if ω = 2π, y(0) = 1 and y′(0) = 0? Homework EquationsThe Attempt at a Solution So, I have to write some...
  6. T

    About velocity equation in simple harmonic motion

    Homework Statement Actually this is not a problem. This is about something i couldn't understand. Homework Equations where wt equals θ The Attempt at a Solution I can understand that x=r.cosθ it is obvious. But i can't understand why Vx=-V.sin(w.t) When i take a triangle from that...
  7. J

    Green function for forced harmonic oscillator

    Homework Statement The problem requires to solve the integration to find ## G(t) ## after ##G(\omega)## is found via Fourier transform. We have G(\omega)= \frac{1}{2\pi}\frac{1}{\omega _{0}^2 - \omega ^2} Homework Equations As mentioned previously, the question asks to find ##G(t)## The...
  8. teroenza

    Harmonic Osclillator Purturbation Matrix Elements

    Homework Statement I am trying to follow Sakurai's use of perturbation theory on a harmonic oscillator, Homework Equations Perturbation: v=\epsilon x^2 , \epsilon << 1 Matrix elements: V_{km}=<k|v|m> The Attempt at a Solution The book says that all other matrix elements besides V_{00}...
  9. A

    Simple Harmonic Motion equation question: which length and why

    Homework Statement I solved this physics question, but I am unclear about why Amplitude was the amount the spring was stretched by (which should be the new equilibrium point), instead of the amount the person pulled the mass down by (which should be the amplitude). Can anyone help? On your...
  10. sergiokapone

    Harmonic oscillations of the electromechanical system (normal modes)

    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}...
  11. B

    Simple Harmonic Motion Pendulum problem

    Homework Statement A simple pendulum of length =30.0cm is released from rest from an angle of θ=10.0∘ to the vertical. Assuming that the pendulum undergoes simple harmonic motion, find its maximum speed. Source: https://isaacphysics.org/questions/accuracy_shm_pendulum_num Homework Equations a)...
  12. NATURE.M

    Comparing Maximum Speeds in Critically Damped and Undamped Harmonic Motion

    Homework Statement A mass on the end of a spring is released from rest at position x0. The experiment is repeated, but now with the system immersed in a fluid that causes the motion to be critically damped. Show that the maximum speed of the mass in the first case is e times the maximum speed...
  13. J

    Interpreting Simple Harmonic Motion Graphs

    Homework Statement Explain the shape of the velocity-displacement and acceleration-displacement graphs for an object undergoing simple harmonic motion. The graph is attached to this thread Homework Equations v = wsqrt(A^2-x^2) where w = angular frequency, A = amplitude and x = displacement...
  14. P

    A gaussian wavefunction of the harmonic oscillator

    Homework Statement A particle of mass m in the harmonic oscillator potential V(x) = (mω2x2)/2 is described at time t = 0 by the wavefunction χ(x, t = 0) = 1/[(2πσ2)1/4] exp[-x2/(4σ2)] What is <E> at time t? Homework EquationsThe Attempt at a Solution <T>+<V>= <E> I've found the expectation...
  15. A

    Simple Harmonic Motion Guitar String Question

    Homework Statement Question: "The midpoint of a guitar string oscillates with an amplitude of 2.24mm with a frequency of 400Hz. Calculate: i) The maximum speed at this point ii) The maximum acceleration of the string at this point" Homework Equations Suitable formulas: x=Asin(2*pi*f*t) ...
  16. P

    Simple Harmonic Motion: Why is acceleration positive at maximum displacement?

    For example, I have a pendulum with amplitude of 2m, when the pendulum is at a displacement of 2m, wouldn't the acceleration be negative as the restoring force is acting towards equilibrium? The equation I am taught is that maximum acceleration is (2*pi*frequency)^2 * amplitude, which is a...
  17. PsychonautQQ

    Understanding Angular Displacement in Weakly Damped Harmonic Oscillators

    Hey PF. This isn't a homework question and I'm hoping this is the right place to ask it, sorry if it isn't! In the case of a weakly damped harmonic oscillator driven by a sinusoidal force of the form Fe^(iwt). The form of the differential force equation of motion is then given by ma + cv +kx =...
  18. P

    What is the effect of the buoyant force on the harmonic oscillator problem?

    I have the following homework problem that I am having trouble with. Any guidance would be appreciated. Thank you in advance. Consider an object hanging on a spring, immersed in a cup of water. The water exerts a linear viscous force -bv on the object, where v is the speed of the object...
  19. C

    Singularities in the harmonic oscillator propagator

    Hi people! Today I was doing some QFT homework and in one of them they ask me to calculate the Harmonic Oscillator propagator, which, as you may know is: W(q_2,t_2 ; q_1,t_1) = \sqrt{\frac{m\omega}{2\pi i \hbar \sin \omega (t_2-t_1)}} \times \exp \left(\frac{im\omega}{2\hbar \sin \omega...
  20. S

    3DAnisotropic oscillator in Spherical Harmonic basis-States with L_z=0

    I've been trying to prove a rather simple looking concept. I have a code that calculates states of a 3D anisotropic oscillator in spherical coordinates. The spherical harmonics basis used to expand it's solutions in radial coordinate constraint the spectrum such that when the Hamiltonian is...
  21. A

    Looking for a good book on harmonic oscillations

    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!
  22. T

    Simple harmonic motion platform

    1. A platform is executing simple harmonic motion in a vertical direction with an amplitude of 5 cm and a frequency of 10/pi vibrations per second. a block is placed on the platform at the lowest point of its path. a) at what point will the block leave the platform? b)how far will the block...
  23. L

    Gravitational force in simple harmonic motion

    Homework Statement I am trying to derive the formula for simple harmonic motion of a mass hanging on a spring. I understand the derivation for the situation when the mass and the spring are on an horizontal table. Then I go about deriving the same formula for the situation when a mass is...
  24. H

    Finding Max Velocity For Simple Harmonic Spring problem?

    Homework Statement A 100kg bungee jumper attached to a bungee cord jumps off a bridge. The bungee cord stretches and the man reaches the lowest spot in his descent before beginning to rise. The force of the stretched bungee cord can be approximated using Hooke's law, where the value of the...
  25. H

    Simple Harmonic Motion Pendulum, can we use PE=1/2kAmplitude^2?

    I was wondering if we can somehow use the formula Potential Energy = 1/2K(x(x=Amplitude))^2 for a pendulum if we are only given the angle of displacement? Would the problems normally just say the PE at the top of the pendulum is such and such, please find max Velocity, Or also the max...
  26. A

    Under-damped simple harmonic motion solution derivation

    I have learned in 1st year that the under-damped simple harmonic motion can be described by the differential equation m \frac {d^2 x} {dt^2} + b \frac {dx} {dt} + kx = 0 where m is the mass, b is the constant of linear drag and k is the spring constant But the derivation is skipped...
  27. I

    Conservation of energy in an undamped driven harmonic oscillator

    This isn't homework. I'm reviewing physics after many years of neglect. Since a simple harmonic oscillator is a conservative system with no energy losses, then a driven undamped harmonic oscillator, once the transient solution has died out, can't be receiving any energy from the driving...
  28. N

    Is the propagation of a wave simple harmonic motion?

    Is the propagation of a wave simple harmonic motion? Simple harmonic motion is defined when the restoring force is proportional to the displacement. Hooke's Law F = -kx is an example. However at my level of understanding I have not yet read about the relationship between forces and waves and...
  29. samgrace

    Energy Levels of Half Harmonic Oscillator

    Homework Statement A harmonic oscillator of mass m and angular frequency ω experiences the potential: V(x) = 1/2mω^{2}x^{2} between -infinity < x < +infinity and solving the schrodinger equation for this potential yields the energy levels E_n = (n + 1/2)...
  30. S

    Relation between harmonic oscillator potential and spin

    Homework Statement The spin 1/2 electrons are placed in a one-dimensional harmonic oscillator potential of angular frequency ω. If a measurement of $$S_z$$ of the system returns $$\hbar$$. What is the smallest possible energy of the system? Homework Equations...
  31. D

    3-D harmonic oscillator expectation value

    Homework Statement The Hamiltonian for the 3-D harmonic oscillator in spherical polar coordinates is given in the question.The question then asks : using the trial wavefunction ##ψ=e^(-αr) ## show that Homework Equations ##<ψ|H|ψ>/<ψ|ψ> = (\hbarα)^2/2m + 3mω^2/2α^2## The following...
  32. M

    Harmonic oscillator (quantum vs classical)

    (I am referring to section 3.1 in Burkhardt's "Foundations of Quantum Physics", if you happen to have the book.) In that book it's pointed out that the apparent contradiction between the pdf's of the QM ground state solution to the harmoinc oscillator with its classical conterpart (at the...
  33. 2

    Why is a pendulum only simple harmonic motion for small angles?

    Homework Statement Hi all! I'm slightly confused about pendulums and simple harmonic motion. In my textbook, it says that a pendulum only exhibits simple harmonic motion when the angle is small (<10 degrees). I was wondering why this is, using equations if possible. Without the math, I think...
  34. T

    Quantum harmonic potential problem

    Homework Statement Consider a particle of mass m in a harmonic potential: If the particle is in the first excited state (n = 1), what is the probability of finding the particle in the classically excluded region? Homework Equations The Attempt at a Solution I sub in...
  35. F

    2D Harmonic Oscillator example

    Hello Forum, The 1D harmonic oscillator is an important model of a system that oscillates periodically and sinusoidally about its equilibrium position. The restoring force is linear. There is only one mode with one single frequency omega_0 (which is the resonant frequency). What about the...
  36. D

    2D quantum harmonic oscillator in cylindrical coordinates (radial part

    Dear kind helpers, actually I am not 100% sure whether this is the right place to post, as it is not a homework in the sense of an exercise sheet. But I think it could be because it feels pretty basic and that I should be able to solve it. Though I really searched for a solution but could not...
  37. M

    What is <x_1-x_2> for two particles in a 1-D harmonic oscillator

    if we have two non-interacting particles of mass M in a one-dimensional harmonic oscillator potential of frequency ω, with the wavefunction defined as: $$\Psi\left(x_1,x_2\right) = \psi_n\left(x_1\right) \psi_m\left(x_2\right)$$ where x_1 and x_2 are two particle co-ordinates. and ψ_n is the...
  38. M

    Modified Harmonic Oscillator probabilities

    Homework Statement The e-functions for n=0,1,2 e-energies are given as psi_0 = 1/(pi^1/4 * x0^1/2)*e^(x^2/(2*x0^2) psi_1 =... psi_2 =... The factor x0 is instantaneously changed to y= x0/2. This means the initial wavefunction does not change. Find the expansions coefficients of the...
  39. Greg Bernhardt

    What is a simple harmonic oscillator

    Definition/Summary An object (typically a "mass on a spring") which has a position (or the appropriate generalization of position) which varies sinusoidally in time. Equations x(t)=A\sin(\omega t)+B\cos(\omega t) \omega^2 =\frac{k}{m} Extended explanation According to...
  40. Greg Bernhardt

    What is a quantum harmonic oscillator

    Definition/Summary This is the quantum-mechanical version of the classical harmonic oscillator. Like the classical one, the quantum harmonic oscillator appears in several places, and it also appears in the quantization of fields. This article will discuss the one-dimensional version, but it...
  41. E

    Simple Harmonic Oscillator on a smooth surface

    I feel I understand what happens, and how to solve the equation of motion x(t) for a mass attached to a spring and released from rest horizontally on a smooth surface. We typically end up with x(t) = x_0 cos(ωt) as the solution, with x_0 as the amplitude of the oscillation. But I've...
  42. carllacan

    Perturbation of a degenerate isotropic 2D harmonic oscillator

    Homework Statement A two-dimensional isotropic harmonic oscillator of mass μ has an energy of 2hω. It experiments a perturbation V = xy. What are its energies and eigenkets to first order? Homework Equations The energy operator / Hamiltonian: H = -h²/2μ(Px² + Py²) + μω(x² + y²) The...
  43. G

    Simple harmonic motion and circular motion

    why simple harmonic motion is projected as or compared with uniform circular motion ?
  44. B

    Cyclic symmetry - harmonic load components

    I have a homework problem where I have to solve for the displacements of the attached system using cyclic symmetry. To do this, I know that I have to find the harmonic load components of the system. One thing that my professor did not make clear (or if he did, I missed it) is how to determine...
  45. G

    Simple harmonic motion and positive constant w^2?

    in defining the Equation of simple harmonic motion taking origin as fixed point and the line of motion as x axis. a(acceleration) = - w^2 * x. where w^2 is positive constant. what is the reason behind taking square of w as constant not just w?
  46. J

    Hamiltonian for classical harmonic oscillator

    I am working through Leonard Susskinds 'the theoretical minimum' and one of the exercises is to show that H=ω/2(p^2+q^2). The given equations are H=1/2mq(dot)^2 + k/2q^2, mq(dot)=p and ω^2=k/m. q is a generalisation of the space variable x, and (dot) is the time derivative if this helps...
  47. carllacan

    Expectation values for an harmonic oscillator

    Homework Statement Find the expectation values of x and p for the state \vert \alpha \rangle = e^{-\frac{1}{2}\vert\alpha\vert^2}exp(\alpha a^{\dagger})\vert 0 \rangle, where ##a## is the destruction operator. Homework Equations Destruction and creation operators ##a=Ax+Bp##...
  48. E

    What is the potential energy at 1/2A in simple harmonic motion?

    A particle of mass is connected to a spring with a force constant K. The particle undergoes simple harmonic with an amp A. What is the potential energy of the partic when the position is (1/2A)? Homework Equations E=1/2kA^2 1/2kdelta^2=1/2mv^2+1/2kx^2 The Attempt at a Solution...
  49. nomadreid

    Damped harmonic motion with one end without weight free

    Homework Statement A block on a horizontal surface is attached to two springs whose other ends are fixed to walls. A light string attached to one side of the block initially lies straight across the surface. The other end of the string is free to move. There is significant friction between...
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