Harmonic Definition and 1000 Threads

  1. H

    Problems of statics, angular motion and simple harmonic motion

    All Questions are shown on pictures. My Calculated answers: A1(a) R= 19.21∠68.7o N (b) E = 19.21∠-111.34o N or = -19.21∠68.7o N <--- Is't either one answer is correct or not? If not, which answer is correct and why? Thanks. A2(b) I = 0.5mr2 = 1.125kgm2 A2(a) k=(I/m)1/2 = 0.212m...
  2. D

    Ground level energies (Particle in a box vs Harmonic Osc.)

    Hello. I have a tiny question that has confused me. Currently I'm reading about potential wells, harmonic oscillators, the free particle in quantum physics. If I just take the particle in a box as an example you have a region where the potential is zero, and you have some walls/boundaries...
  3. F

    Perturbed in the harmonic oscillator

    Homework Statement Homework Equations The Attempt at a Solution for part a I do not know how to write it in power series form ? for part b : I chose the perturbed H' is v(x)= (1+ε )K x^2 /2 then I started integrate E_1 = ∫ H' ψ^2 dx the problem was , the result equals to ∞ ! shall I...
  4. R

    Finding general solution of motion of forced harmonic oscillator

    [b]1. The motion of a forced harmonic oscillator is determined by d^2x/dt^2 + (w^2)x = 2cos t. Determine the general solution in the two cases w = 2 and w is not equal to 2. To be honest I've no idea where to start!
  5. T

    Simple Harmonic Motion Problem 4

    Hi friends the problem is - https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-prn1/s480x480/155412_2656530589803_1383873256_n.jpg Attempt - As per the problem states, When the compound system will oscillate in its natural frequency, The frequency of the oscillation will be, √[k/(m...
  6. T

    Simple Harmonic Motion Typical Problem

    Hi friends the problem is - https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-prn1/s480x480/60061_2656517749482_1458399262_n.jpg Attempt - As per the problem states, The net force on the particle will be ...
  7. T

    How Does Phase Affect Direction in Simple Harmonic Motion?

    Hi friends the problem is - https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-ash4/430884_2656507629229_1511525381_n.jpg Attempt - friend as per the question I am trying to get structure of SHM, The displacement equation x = A sin(ωt + θ) represents SHM where ωt + θ is Phase of the...
  8. T

    Solving Simple Harmonic Problem 2: Acceleration-Displacement Equation Help

    Hi friends the problem is - https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-prn1/30370_2656498989013_1471109032_n.jpg Attempt - friends as per the question I am trying to get the acceleration- displacement equation for this problem. So I am using F = - (dU / dx)...
  9. T

    Simple Harmonic Motion problem 1

    Hi friends the problem is - https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-snc6/s480x480/6405_2656465868185_1414230035_n.jpg Attempt - As per the problem states, For the first second equation of SHM, (using x = A sin ωt) a = A sin ω From here I get, sin ω = a/ A...
  10. sankalpmittal

    Question regarding Simple Harmonic Motion

    Homework Statement The two linear simple harmonic motions of equal amplitudes , and angular frequencies ω and 2ω are imposed on a particle along the axes of X and Y respectively. If the initial phase difference between them is π/2 , then find the resultant path followed by the particle...
  11. R

    Quantum Harmonic Oscillator - Why we limit the bottom end of the ladder

    Hi All, If there is something fundamentally wrong in my understanding of quantum mechanics, pardon me for I have just started learning it. We know that if we can come up with a solution for Schrodinger Equation of a Harmonic Oscillator, then we can generate further solutions by acting on it...
  12. DiracPool

    Yo-yoing over the harmonic oscillator

    I've been looking around and trying to figure it out, but I can't seem to figure out how the cosine function get's into the solution to the HO equation d2x/dt2=-kx/m. I know this is extremely basic, but could someone indulge me?
  13. D

    What Is the Velocity of a Mass on a Spring When Displacement Is 3.6 cm?

    Homework Statement This is a 3 part problem and I've successfully solved the first 2 parts, but I don't know what I did wrong in the third part. 1) mass of 346 g on a spring with constant 26.8 N/m on a horizontal + frictionless surface. Amplitude is 6.7 cm. In part 1 i found the total...
  14. R

    [coupled harmonic oscillators] old thread- need elaboration

    Hi Can someone please explain the answer to the following thread? I tried uncoupling the Hamiltonian but to no avail. https://www.physicsforums.com/showthread.php?t=602106 Thank you.
  15. A

    Solving Doubled Spring Constant in Harmonic Oscillator

    A particle has its wave function as the ground state of the harmonic oscillator. Suddenly the spring constant doubles (so the angular frequence dobules). Find the propability that the particle is afterwards in the new ground state. I did solve this, it was quite easy. But doing so I encountered...
  16. U

    Generalization of the bohr rule for harmonic oscillators

    Homework Statement The generalization of the bohr rule to periodic motion more general than circular orbit states that: ∫p.dr = nh = 2∏nh(bar). the integral is a closed line integral and the bolded letters represent vectors. Using the generalized, show that the spectrum for the...
  17. J

    Quantum Mechanical Harmonic Oscillator Problem Variation

    Homework Statement At time t < 0 there is an infinite potential for x<0 and for x>0 the potential is 1/2m*w^2*x^2 (harmonic oscillator potential. Then at time t = 0 the potential is 1/2*m*w^2*x^2 for all x. The particle is in the ground state. Assume t = 0+ = 0- a) what is the probability that...
  18. W

    Simple Harmonic Motion: Period Dependence on Variables and Curve Fitting

    Homework Statement I'm doing a lab, and they want me to show the dependence of the period on different variables (displacement, mass, and length of pendulum). They ask me to "Fit curves to your plots to show the dependence. Use the curve fits from your plots to devise an equation for...
  19. H

    Simple harmonic motion,the restoring force?

    at the extreme position, the restoring force that developed, is it's magnitude more than the initial force imparted? and that's why it goes back to the mean position or is it that, the magnitude is same and it just goes back to attain stable equilibrium?.
  20. U

    Harmonic Mean of Roots: Solving a Quadratic Equation with Complex Terms

    Homework Statement The harmonic mean of the roots of the equation (5+\sqrt{2})x^2-(4+\sqrt{5})x+8+2\sqrt{5}=0 Homework Equations The Attempt at a Solution I know this question is easy but the main problem arises in finding the roots of the above equation. When I use the quadratic...
  21. K

    Simple harmonic motion of a machine part

    Homework Statement A machine part is undergoing SHM with a frequency of of 5hz and amplitude of 1.80cm. How long does it take the part to go from x = 0 to -1.80cm? Homework Equations x = Acoswt The Attempt at a Solution X is given and convert it to metres 0.018. I need to...
  22. J

    Expectation values of harmonic oscillator in general state

    So, this has been bothering me for a while. Lets say we have the wavefunction of a harmonic oscillator as a general superposition of energy eigenstates: \Psi = \sum c_{n} \psi _{n} exp(i(E_{n}-E_{m})t/h) Is it true in this case that <V> =(1/2) <E> . I tried calculating this but i...
  23. D

    Simple Harmonic Motion and equilibrium

    Homework Statement A 93-kg box hangs from the ceiling of a room—suspended from a spring with a force constant of 540 N/m. The unstressed length of the spring is 0.505 m. (a) Find the equilibrium position of the box. (b) An identical spring is stretched and attached to the ceiling and the box...
  24. X

    I do not why the particle does the simple harmonic motion.

    Homework Equations I do not why the particle does the simple harmonic motion. And how to find such innitial condition to satify r decreases continually in time. [b]3. The Attempt at a Solution [/b Is it need to take derivative of r?
  25. H

    Simple harmonic motion of guitar string

    Homework Statement I have a question pertaining to the simple harmonic motion of the midpoint of a guitar string with a frequency of 4.40 x 10^2 Hz and an amplitude of 1.60 mm. I've been asked to deduce the initial displacement, velocity and acceleration of the midpoint of the string, but am a...
  26. T

    Harmonic Motion Lecture: Deriving Equations

    I had a lecture regarding harmonic motion. he also derived equation related to pendulum motion with extended object and equation is following.(motion is a simple harmonic motion) d^2θ/dt^2+(RcmMg)θ/I=0 θ(t) = θcos(Ωt)+(ω/Ω)sin(Ωt) where Ω is defined angular frequency oscillation for all...
  27. J

    Variational Principle of 3D symmetric harmonic oscillator

    Homework Statement Use the following trial function: \Psi=e^{-(\alpha)r} to estimate the ground state energy of the central potential: V(r)=(\frac{1}{2})m(\omega^{2})r^{2} The Attempt at a Solution Normalizing the trial wave function (separating the radial and spherical part)...
  28. S

    Simple harmonic motion-experiment

    Homework Statement I was being asked to find the limitation and possible ways to improve the following experiment Cantilever experiment to record the time of fixed oscillations as the length of the ruler with a fixed mass increases each time. The Attempt at a Solution Limitation-air...
  29. D

    How is the Sine Term Transformed in the Harmonic Motion Equation?

    I'm trying to work out the differential equation for simple harmonic motion without damping, x''+\frac{k}{m}x = 0 I can solve it to x = c_1cos(\sqrt{\frac{k}{m}}) + c_2sin(\sqrt{\frac{k}{m}}) But the generalized solution is x = Acos(\omega*t + \delta) where A = \sqrt{c_1^2 + c_2^2}...
  30. D

    Simple Harmonic Motion without damping

    So, simple harmonic motion without damping is described generally by x(t) = Acos(\omega*t +\delta) Which is derived from the differential equation x''+\frac{k}{m}x = 0 We know that A = \sqrt{c_1^2+c_2^2} and tan\delta = \frac{c_1}{c_2} With the differential equation, dealing...
  31. N

    Sum of the sum of harmonic series?

    Homework Statement Does this converge or diverge? Ʃ1/(1+2+3+4+5...+n), as n---> infinity?The Attempt at a Solution I rewrote this into Ʃ(Ʃ1/n) (is it correct?). I figured that since Ʃ(1/n) diverges, then the sum of each partial sum most (obviously) also diverge. However, it appears I'm...
  32. S

    What is a space/spatail harmonic?

    What is a space/spatial harmonic? Hi I am doing a project on folded waveguides and I am reading some IEEE papers for literature review. I always come across this term "space harmonic" and fail to understand what it is. I have checked online but don't get it. Even posted in the Electrical...
  33. D

    Does a Closed Form Exist for the Harmonic Series?

    HI! I was wandering if there is a proof that the harmonic sum \sum\frac{1}{k} has no closed form. Something like the proof that an equation with degree more than 4 has no solution in terms of radicals.
  34. T

    Harmonic Plane Wave: Form & Explanation

    Hi, why does the harmonic plane wave have the form below: V(r,t)= acos[\omega (t-\frac{r\cdot s}{v})+\delta ] (r is the position vector, s is the vector that points to the direction the wave is propagating, v is the wave propagation velocity and delta is the phase constant).
  35. G

    Proving S2n-Sn is greater than a half in terms of the harmonic series

    Homework Statement Let Sn = 1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}...+\frac{1}{n}. Show that |S2n-Sn|\geq \frac{1}{2} Homework Equations The Attempt at a Solution So I'm going to try and use induction Base case let n=1 |S2n-Sn| = \frac{1}{2} So true for base case...
  36. V

    How can a Personal Computer be used as a load in Harmonic Monitoring?

    Hi,I am Vikas Joshi and I'm studying last year Electronics Engineering. I am doing project on Harmonics Monitoring using Micro-controllers. I have some doubts about it.They are as follows: 1.How to detect Harmonics from Single Phase supply.What kind of circuits I should use to detect specific...
  37. V

    Derivations of Harmonic Oscillator Laws

    When people talk about harmonic oscillators it seems to me that they always assume either that the relationship of force and displacement is linear, or that it behaves in some sinusoidal fashion. Do you always have to assume one to be able to arrive at the other? Or is there something I'm...
  38. E

    Simple harmonic motion problem help.

    Homework Statement particle experiencing SHM with frequency f= 10 hz find the displacement x at any time t for the following initial conditions. @ t=0 x=0.25m v=0.1 m/sHomework Equations x=Asin(ωt+∅) v=Aωcos(ωt+∅)The Attempt at a Solution So with frequency I find ω which then is subbed into...
  39. A

    Canonical transformation for Harmonic oscillator

    Find under what conditions the transformation from (x,p) to (Q,P) is canonical when the transformation equations are: Q = ap/x , P=bx2 And apply the transformation to the harmonic oscillator. I did the first part and found a = -1/2b I am unsure about the next part tho: We have the...
  40. J

    Eigenstate for a 3D harmonic oscillator

    Homework Statement A 3D harmonic oscillator has the following potential: V(x,y,z) = \frac{1}{2}m( \varpi_{x}^2x^2 + \varpi_{y}^2y^2 + \varpi_{z}^2z^2) Find the energy eigenstates and energy eigenvalues for this system. The Attempt at a Solution I found the energy eigenvalue to...
  41. S

    Understanding Simple Harmonic Motion: The Role of Frequency in Wave Equations

    I was reading a book on wave and found that when they derive the equation of shm from the equation force varies with negetive displacement , they had taken a propotionality constant to make the force and displacement equal and they had taken frequency of the shm as the constant . So my question...
  42. J

    Finding energy eigenvalue of a harmonic oscillator using a Hamiltonian

    Homework Statement Find the energy eigenvalue. Homework Equations H = (p^2)/2m + 1/2m(w^2)(x^2) + λ(x^2) Hψ=Eψ The Attempt at a Solution So this is what I got so far: ((-h/2m)(∂^2/∂x^2)+(m(w^2)/2 - λ)(x^2))ψ=Eψ I'm not sure if I should solve this using a differential...
  43. C

    What does the phase angle phi mean in the harmonic oscillation function?

    The function for simple harmonic oscillation is: Acos(ωT)+\phi Why is there an angle phi added to the function acos(ωT)?
  44. P

    Energy Eigenstates of a Perturbed Quantum Harmonic Oscillator

    Homework Statement (See attachment) Homework Equations x = \sqrt{\frac{\hbar}{2m \omega}} ( a + a^{\dagger} ) x = i \sqrt{\frac{\hbar m \omega}{2}} ( a^{\dagger} - a ) The Attempt at a Solution In part a) I was able to construct a separable Hamiltonian for the harmonic...
  45. C

    Underdamped harmonic oscillator with a sinusoidal driving force

    Homework Statement Consider an underdamped harmonic oscillator (Q > 1/2) with a sinusoidal driving force Focos(ωdt). (a) (5 pts) By using differential calculus find ωd that maximizes the displacement amplitude. (b) (7 pts) By using differential calculus find ωd that maximizes the velocity...
  46. H

    Period for harmonic motion (horizontal)

    Consider a light flexible rod placed on a horizontle table with part of the rod (length say "x") hanging freely (ie without support of the table) see attachment for clarity A mass is also hung from the rod t one end. Are there any equations that relate the Period T of the end of the rod to...
  47. S

    Prove Heisenberg Uncertainty Principle for Ground State Harmonic Oscillator

    Ground State Wave Equation: ψ0=(a/∏)(1/4)e(-ax2/2) Prove the Heisenberg Uncertainty principle ≥h(bar)/2 by way of expectation values. First I found <x>=0 because it was an odd function then I found <Px>=0 because it was an odd function Then <x2>=∫(a/∏)(1/2)x2e(-ax2)/2dx=1/2a by way of...
  48. M

    Lorentz Force or Simple Harmonic Motion

    So my friend and I were going through problems and this came up... Consider 3 straight, infinitely long, equally spaced wires (with zero radius, separated each by a distance d), each carrying a current I in the same direction. blah blah blah... part c) asks us... If the middle...
  49. H

    Forced Harmonic Oscillator C Cos wt dC/dt = 0

    I believe this is pretty standard. Given a mass m on a spring with spring constant k, a solution to the second order differential equation of motion m\ddot{x} = -kx, is x = cos ωot, and ωo = \sqrt{k/m}. If that same oscillator is driven with a force F(t) = Fo cos ωt the equation of motion...
  50. S

    Simple Harmonic Oscillator: Kinetic and Potential Energy Equilibrium

    Homework Statement A simple harmonic oscillator has an amplitude of 0.1 m. At what displacement will its kinetic and potential energies be equal? Homework Equations The Attempt at a Solution I'm trying to figure out how to solve this problem but I'm totally stuck and even don't...
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