Harmonic Definition and 1000 Threads

  1. TomW17

    Natural frequency of a simple harmonic system

    Homework Statement Derive the natural frequency f_n of the system composed of two homogeneous circular cylinders, each of mass M, and the connecting link \text{AB} of mass m. Assume small oscillations. Homework Equations The sum of the kinetic + potential energies in an isolated system...
  2. Q

    Harmonic oscillator coherent state wavefunction

    Hi, I am trying to find the wavefunction of a coherent state of the harmonic oscillator ( potential mw2x2/2 ) with eigenvalue of the lowering operator: b. I know you can do this is many ways, but I cannot figure out why this particular method does not work. It can be shown (and you can find...
  3. D

    Finding mechanical energy of simple harmonic oscilator

    Homework Statement A simple harmonic oscillator consists of a block of mass 45 g attached to a spring of spring constant 240 N/m, oscillating on a frictionless surface. If the block is displaced 3.5 cm from its equilibrium position and released with an initial velocity of 2.5 m/s, what is its...
  4. D

    Simple Harmonic Motion and phase constant

    A simple harmonic oscillator consists of a block of mass 45 g attached to a spring of spring constant 240 N/m, oscillating on a frictionless surface. If the block is displaced 3.5 cm from its equilibrium position and released so that its initial velocity is zero, what is the phase constant, φ ...
  5. B

    Showing harmonic series is divergent

    Homework Statement Homework Equations Where do the terms 1/4 come from? Are they ambiguous? The Attempt at a Solution Trying to understand the text[/B]
  6. T

    How Do You Transform Trigonometric Expressions and Find Their Extremes?

    Homework Statement Express $$4sin\theta-3cos\theta$$ in the form $$rsin(\theta-\alpha)$$ Hence find the maximum and minimum values of $$\frac{7}{4sin\theta-3cos\theta+2}$$ State the greatest and least values. Homework EquationsThe Attempt at a Solution Okay so putting it in the...
  7. D

    Quantum harmonic oscillator inner product

    Homework Statement Using the equations that are defined in the 'relevant equations' box, show that $$\langle n' | X | n \rangle = \left ( \frac{\hbar}{2m \omega} \right )^{1/2} [ \delta_{n', n+1} (n+1)^{1/2} + \delta_{n',n-1}n^{1/2}]$$ Homework Equations $$\psi_n(x) = \left ( \frac{m...
  8. M

    Simple Harmonic Motion of a 12kg mass

    A 12kg mass undergoes simple harmonic motion with an amplitude of 10cm. If the force constant for the spring is 320N/m: a) Calculate the total energy of the mass spring system. Et=½kA^2 =½(320N/m)(0.1m)^2 =1.6 Jb) Calculate the maximum speed of the mass. Et=½mv^2 + ½kx^2 1.6 J = ½(12kg)v^2...
  9. SuperSpasm

    Why do two textbooks have conflicting equations for the harmonic wave equation?

    Homework Statement I'm using a couple different textbooks on waves, and it seems they've possibly contradicted one another. I think the problem may be that one deduced the equation for displacement in a transverse harmonic wave y(x,t) through the equation for displacement at t=0 [y(x,0)] and...
  10. S

    Simple Harmonic Oscillator Zero Probability Points

    Hi, What is the physical meaning of zero probability of finding a particle in the square of the Quantum SHO wave function? the particle is supposed to oscillate about the equilibrium position, how would it go from an end point to the other end point without passing by certain points? Could the...
  11. AwesomeTrains

    Maximum position expectation value for 1D harmonic oscillator

    Hey, I'm stuck halfway through the solution it seems. I could use some tips on how to continue. 1. Homework Statement I have to determine a linear combination of the states |0\rangle, |1\rangle, of a one dimensional harmonic oscillator, so that the expectation value \langle x \rangle is a...
  12. Q

    Harmonic motion and Electrical Fields

    Homework Statement Two positive charges +Q are affixed rigidly to the x-axis, one at x = +d and the other at x = -d. A third charge +q of mass m, which is constrained to move only along the x-axis, is displaced from the origin by a small distance s << d and then released from rest. (a) Show...
  13. E

    Odd (pretty) waveform for third harmonic of violin E-string

    I lightly placed my finger a quarter of the length down the E-string of a violin and drew the bow, forcing the third harmonic. I used an oscilloscope app to look at the waveform. I got this unusually regular pure pattern...
  14. E

    Difference between X and Amplitude (Simple Harmonic Motion)?

    V=Vo √1-(x^2/a^2) X is the distance of the spring's stretch, but how would you rearrange the equation if you are looking for Amplitude? They both use the same units (meters) as far as I am concerned. Help would be appreciated, thanks; I am still a beginner with Physics.
  15. K

    Question about harmonic poential trap

    Hi there, I am reading something about the bose-einstein condensate, in this material http://www.physics.ox.ac.uk/qubit/fetch.asp?url=groupwebsite/papers/paper103.pdf , it states something called harmonic trap. I read other introduction materials on bose-einstein condensate, it said that to...
  16. Samurai44

    Simple harmonic motion energy question

    Homework Statement Can I get help in part (b) of this question ? Homework Equations KE=1/2 m v2 v= (2π f )√(A2 - x2) The Attempt at a Solution I substituted the second equation into first one, so i got KE= 1/2 m (2π f )2 (A2 - x2) but then couldn't complete
  17. P

    What is the Normalized Ground State Energy of a 3-D Harmonic Oscillator?

    Homework Statement What is the normalized ground state energy for the 3-D Harmonic Oscillator Homework Equations V(r) = 1/2m(w^2)(r^2) The Attempt at a Solution I started with the wave fn in spherical coordinates, and have tried using sep of variables, but keep getting stuck when trying to...
  18. D

    How do I tell what harmonic an instrument is producing?

    Homework Statement An instrument is producing a tone, such as a D4. If I know the frequency of the tone, the length of the instrument but nothing else, how can I find the harmonic at which the tone is produced? The instrument is an open tube. Homework Equations v=wavelength*frequency[/B]...
  19. C

    Calculating Frequency of a Simple Pendulum | Length 80cm

    I'm asked to Calculate the frequency of oscillation of a simple pendulum of length 80cm. As its a pendulum I used To calculate the time. To which I got 4/7π I then used f=1/period and converted 80cm to 0.8m and got a frequency of 0.577Hz, is this correct ?
  20. J

    Integrating acceleration sin wave

    This is a really basic calc/physics question.If acceleration is defined as Acc= Asin(w*t), and I integrate this to get velocity, I get Vel=(-A/w)*cos(w*t)+C. If the velocity at t=0 is 0, then C=A/w. If I then integrate the velocity to get the displacement, I get...
  21. M

    Calculating the Period of a Simple Harmonic Oscillator with a Pivoted Metal Rod

    Homework Statement A L = 1.48 m long metal rod is pivoted from a point one third of the way along its length. The rod has a mass of 0.208 kg. What period will the rod oscillate with when released from a small angle? Homework Equations T = 2 \pi \sqrt{\frac{L}{g}} The Attempt at a...
  22. ChrisVer

    C++ Harmonic Oscillator (with Force)

    I was wondering whether it's possible to write a code in C++ that would be able to solve the Harmonic Oscillator: \ddot{x} + \gamma x = F_{external}(t,x) With different F function inputs... I thought about creating a function with if clauses, so for different inputs by the user, the force F...
  23. moriheru

    Quantum harmonic oscillators DE wavefunction

    My question concerns a really simple differential equation for the zeroth wavefunction of a harmonic oscillator. I have pretty much got it but my solution just differs by a constant,so I thought why think when one can ask other people :). Here is the equation: Where the x star represent a...
  24. L

    Angular Simple Harmonic Motion

    1. The balance spring of a watch is a hoop 1.2 cm in diameter, with a mass of 0.65 g. If the watch is running 45 seconds per day too fast, by what percentage should the rotational inertia of the hoop be changed? 2. Homework Equations : I = mR^2 Ia = -k(theta) x(t) = Xm Cos(wt + @) (just using @...
  25. L

    Simple Harmonic Motion Question (Springs)

    A 350-g mass is attached to a spring whose spring constant is 64 N/m. Its maximum acceleration is 5.3 m/s2. What is its maximum speed? So, i had a go at the question which basically required the knowledge that maximum acceleration occurs when displacement is maximum and maximum velocity occurs...
  26. R

    Hamiltonian of the Half Harmonic Oscillator

    Given the half harmonic potential: \begin{equation}V=\begin{cases}1/2\omega^2mx^2 & x > 0\\\infty & x < 0\end{cases}\end{equation}What will be the Hamiltonian of the half oscillator?I understand that for x>0 the Hamiltonian will be...
  27. shanepitts

    Average kinetic energy of harmonic oscillator

    I was wondering why the average kinetic energy is calculated in this manner. They are dividing the kinetic energy function by the period (noted here as To) and integrating it with limits from 0→To. Why? (This is a tiny portion of a larger textbook example, not an actual assignment.) Sorry for...
  28. C

    Normalisation of harmonic oscillator classical action

    Homework Statement The transition amplitude for the harmonic oscillator may be written as ##\langle x_2, t_2 | x_1, t_1 \rangle = N_{\omega}(T) \exp(i/\hbar S_{cl})##, where ##T=t_2-t_1## and ##S_{cl}## is the classical action. Let the wave function at ##t=0## be ##\psi(x,o) =...
  29. R

    Quantum Mechanics: Harmonic Oscillator

    Homework Statement A particle of mass m in the one-dimensional harmonic oscillator is in a state for which a measurement of the energy yields the values ##\hbar\omega/2## or ##3\hbar\omega/2## each with a probability of one-hald. The average value of the momentum ##\langle p_x\rangle## at...
  30. O

    Find the amplitude of the resulting simple harmonic motions

    Homework Statement An 8.0 lb block is suspended from a spring with a force constant of 3.0 lb/ in. A bullet weighing 0.10 lb is fired into the block from below with a speed of 500 ft/sec and comes to rest in the block. a) Find the amplitude of the resulting simple harmonic motions b) What...
  31. Calpalned

    Relationship between harmonic and circular motions

    Homework Statement How is ##\frac{v}{v_M} = \frac{\sqrt{A^2 - x^2 }}{A}## derived? Homework Equations n/a The Attempt at a Solution I don't see a right angle in the picture anywhere, so I don't see how pythagorean's theorem is valid.
  32. Calpalned

    Understanding Simple Harmonic Motion: Homework Equations and Graph Analysis

    Homework Statement My textbook states that for simple harmonic motion, the sinusoidal graph of the x (displacement) as a function of time can be created using the "Equation of motion". Homework Equations The equation of motion ##A \cos (\omega t + \phi)## The Attempt at a Solution I know...
  33. T

    Simple Harmonic Motion with Damping and Driving

    Hello, I was asked by my professor today to graph the motion, as well as the energies, of a spring that undergoes driven and/or damped oscillation; however, I was unable to because I do not have a very good idea of how they work. Can someone explain to me, qualitatively, what it means to have a...
  34. J

    Can a harmonic be louder than the fundamental frequency?

    This is not a homework question per se, but rather something I have come across during a homework project. Using Audacity, I recorded a few different instruments playing the same notes (investigating timbre). I noticed that (using a steel string acoustic guitar) the first harmonic at 131 Hz...
  35. D

    Harmonic oscillator in Heisenberg picture

    For the harmonic oscillator in 1-D we get the 2nd time derivative of the x Heisenberg operator = -ω2 x. When that is integrated it gives xH (t) = Acos(ω t) +Bsin (ω t) where A and B are time independent operators. My question is why are the constants A and B incorporated into the terms as a...
  36. L

    Simple harmonic motion>Origin?

    Hello there! I have a simple question; Why simple harmonic motion is called simple harmonic motion? What's the origin of this name? I could not find the answer despite browsing so many websites on the internet. Could anybody tell me the answer? Thanks in advance.
  37. S

    Derive equation for Energy of the Harmonic Oscillator

    I'm trying to figure out how to derive the equations for Energy from the differential equation corresponding to the (simple and damped) harmonic oscillator. Please note that I don't want to start with the expressions for kinetic and potential energy, I want to derive them. The references that I...
  38. Runei

    Harmonic oscillator shifted origin

    Hello, I'm was going through the simple harmonic oscillator, just as a recap, and I stumbled upon something which is causing me wonder. I'm solving the SHO with a shifted origin, and so I have the differential equation F=-k(x-x_0) \ddot{x}=-\frac{k}{m}x+\frac{kx_0}{m} Now, I get that I can...
  39. Shackleford

    Determine whether functions are harmonic

    Homework Statement Determine whether or not the following functions are harmonic: u = z + \bar{z} u = 2z\bar{z} Homework Equations z = u(x,y) + v(x,y)i \bar{z} = u(x,y) - v(x,y)i A function is harmonic if Δu = 0. The Attempt at a Solution Δu = Δz +Δ \bar{z} = u_{xx} + v_{xx} +...
  40. Entanglement717

    1D Harmonic Oscillator in a Constant Electric Field

    Homework Statement Hello, I'm just curious as to whether I'm going about solving the following problem correctly... Problem Statement: A particle mass m and charge q is in the ground state of a one -dimensional harmonic oscillator, the oscillator frequency is ω_o. An electric field ε_o is...
  41. P

    Undamped Harmonic Oscillator Problem

    Homework Statement Find the initial conditions for 2 interchangeable harmonic oscillators (undamped) so that they have the same amplitude of oscillation. Homework Equations x(t)=Xm*cos(wt+ϕ)The Attempt at a Solution The amplitude of the function is given by Xm so I would have thought that just...
  42. Futurestar33

    Given a harmonic oscillator with mass m, and spring constant

    Homework Statement Given a harmonic oscillator with mass m, and spring constant k, is subject to damping force F= cdx/dt and driven by an external force of the form F[ext]= FoSin(wt). A) Find the steady state solution. B) Find the amplitude and the phase. Homework Equations F=-kx the steady...
  43. C

    Time dependent perturbation theory of the harmonic oscilator

    Homework Statement A 1-d harmonic oscillator of charge ##q## is acted upon by a uniform electric field which may be considered to be a perturbation and which has time dependence of the form ##E(t) = \frac{K }{\sqrt{\pi} \tau} \exp (−(t/\tau)^2) ##. Assuming that when ##t = -\infty##, the...
  44. P

    Classical Limit of a Quantum Harmonic Oscillator

    I seem to have two approaches that I've seen and understand, but I can't quite see how they relate. 1. Write a general time evolving state as a superposition of stationary states multiplied by their exp(-iEt/h) factors, and calculate <x>. We find that <x>=Acos(wt+b) as in classical physics (in...
  45. Fyj

    Finding the force in a simple harmonic lattice

    Homework Statement If there are a large number of ions oscillating in a straight line, we can pick the nth one oscillating about its equilibrium a*n. The potential of the entire lattice is then U = 0.5*K[u(an)-u([n+1]a)]^2 - summed over all n. How do I use Force = -dU/du(an) to derive that...
  46. M

    Simple Harmonic Motion: Particle Speed and Acceleration Calculation

    Homework Statement A particle moves with simple harmonic motion in a straight line with amplitude 0.05 m and the period 12 s.Find (a) the maximum speed , (b) the maximum acceleration of the particle.Write down the values of the constants P and Q in the equation x/m = P sin [Q)(t/s)] Homework...
  47. A

    Finding Harmonic Vibration from Frequency

    can we find the harmonic of vibration somehow just by knowing frequency?
  48. Futurestar33

    Harmonic Motion in One dimension -- Question in equation derivation

    Homework Statement I am curious as to how the second line in the equation is equal to the third line in the equation. The book my class is using is Taylor and it just skips so many steps. What happens to the sign, I know this must relate to euler in some way I am just not sure how. Thank you...
  49. kate Co

    Simple Harmonic Motion Question?

    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...
  50. gfd43tg

    Ladder operators to find Hamiltonian of harmonic oscillator

    Hello, I was just watching a youtube video deriving the equation for the Hamiltonian for the harmonic oscillator, and I am also following Griffiths explanation. I just got stuck at a part here, and was wondering if I could get some help understanding the next step (both the video and book...
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