Amplitude Definition and 868 Threads

The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). There are various definitions of amplitude (see below), which are all functions of the magnitude of the differences between the variable's extreme values. In older texts, the phase of a period function is sometimes called the amplitude.

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  1. 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...
  2. F

    Amplitude of two carts attached by a spring

    Homework Statement #1. [Coupled Oscillators] A cart of mass m (car #1) and another cart of mass 2m (car #2) on a horizontal surface are connected by an ideal massless spring of spring constant k. The two carts are set into oscillation about their center-of-mass (CM) in Simple Harmonic...
  3. C

    Waves - Power spectral density to amplitude

    Hi all, I am trying to simulate ocean waves on a 3d grid of points. I have recently discovered the Pierson Moskowitz spectrum which will give a wave spectral density (ms/hz) for a given wind condition. I am trying to represent this by using a large number (say 64) Gerstner waves. Each wave I...
  4. T

    Covariance betw scalar amplitude & spectral index in Planck?

    I am reading some of "Planck 2013 results. XXII. Constraints on inflation." The paper is full of values for various inflationary parameters under various models, with their confidence intervals. For instance, in Table 5 on page 13, the authors report that — for a model including both running of...
  5. C

    Vout = (a+jb)Vin, what do A and B stand for?

    Homework Statement I was given a graph with two waves on it, the input and output wave. I found the frequency of the waves, change in magnitude and change in phase. The last question asks me to write the transformation from input to output as a phasor and he gave the relevant equation below...
  6. Safinaz

    The amplitude of B decay into tau neutrino

    Hi there, In Reference as hep-ph/0306037v2, we see the effective Hamiltonian of ## B \to l \nu ## equ. 1, which has the SM and the NP parts. In equ. 4, it seems that ## m_l ## comes from ## P^\mu_B ## equ. 3. The question that how ## P^\mu_B ## yields ## m_l ## ? Where ## P^\mu_B = ( E_B, 0...
  7. S

    Phase Difference with Initial Conditions for SHM

    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...
  8. T

    Understanding Intensity and Amplitude of Physical Waves | School Physics UK

    http://www.schoolphysics.co.uk/age16-19/Wave%20properties/Wave%20properties/text/Intensity_and_amplitude/index.html well this may be alittle bit simple but in the link above the energy of a physical wave is shown as squared i mean is this done to eliminate that the positive and negative values...
  9. J

    What are the issues with the covariant partners in this amplitude calculation?

    Hi, I have a question regarding pair production, regarding the amplitude that I am trying to understand. I have attached a photograph of the feynmann diagram, which I believe to be correct - although I don't like the vertex/propogator combination as shown below: (I have split up integral so it...
  10. N

    Double Slit Probability Amplitude Orientation

    Why are the orientations of waves arriving at the screen not considered when adding amplitudes? For example a double slit in 2D has two radial lengths of R1 and R2, one from each source Slit 1 and Slit 2, arriving at point P1. (See attached) The provides a probability amplitude of...
  11. D

    Superposition of two cosine waves

    Homework Statement Superposition of two cosine waves with different periods and different amplitudes. Homework Equations This is basically: acos(y*t) + bcos(x*t) The Attempt at a Solution I looked at different trig functions but it seems it is not a standard solution. I've found solutions...
  12. S

    Simple Harmonic Motion oscillation amplitude

    Homework Statement A mass on a spring has an angular oscillation frequency of 2.56 rad/s. The spring constant is 27.2 N/m, and the system's kinetic energy is 4.16 J when t = 1.56 s. What is the oscillation amplitude? Assume that the mass is at its equilibrium position when t = 0.a. 63.1 cm b...
  13. manjuvenamma

    Is there a relationship between amplitude response and phase?

    Is there a relationship between amplitude and phase response of a realizable filter? For the purpose of ease, let us consider only a FIR digital filter. I would like to design a FIR digital filter with a given frequency response (amplitude and phase responses given as a function of frequency)...
  14. P

    Amplitude of 2 waves at a point

    Homework Statement Two sound sources oscillate in phase at 500Hz with the same amplitude sm. At a point 5m from source 1 and 5.17m from source 2, what is the amplitude? Homework Equations s(x,t)=sm*cos(kx-wt) w=2πf Speed of sound=340m/s The Attempt at a Solution v=340m/s w=2πf=1000π rad/s...
  15. A

    Relation between intensity and amplitude

    When superposing waves in say double slit interference from two slits, I seem to have come across two approaches: 1. Sum the two waves in complex form to get the resultant amplitude, take the real part, and square to get the intensity, i.e I=[Re(A)]2 2. Sum the two waves in complex form to get...
  16. J

    2nd order resonance filter amplitude response(z-parameters)

    Homework Statement A resonance filter is a specific second-order digital system designed to attenuate all frequencies except at and around a given center frequency. The transfer function of a resonance filter is: H(z)=(1 - r)(1 - rz-2) / (1 - 2rcos(ωcT)z-1+r2z-2) where ωc = 2πfc, where fc is...
  17. D

    How can I show that the amplitude of a reflected wave?

    In Feynman Lectures on Physics (you can find it online), chapter 33 of volume 1, the author derives Fresnel's formulas for the coefficient of reflection in an unusual way by making considerations about the different possible polarization of light. In this way he derives the squares of the...
  18. P

    Wave Problem -- Total amplitude of fundamental and first three harmonics

    Homework Statement An acoustic signal is composed of the first three harmonics of a wave of fundamental frequency 463 Hz. If these harmonics are described, in order, by cosine waves with amplitudes of 0.100, 0.300, and 0.760, what is the total amplitude of the signal at time 0.401 seconds...
  19. Z

    Wave Amplification & Frequency Transformation

    I understand the concepts behind the terms in the title; however, I have a question about how to transform the wave energy itself. I'm working on a science fair project that involves transforming sound energy into electrical energy--I understand this is not a very reasonable method of harvesting...
  20. N

    Physics Report Help -- Simple Harmonic motion and Elastic force

    Homework Statement So I have to write a report based on an experiment that I have conducted. I know that my report is connected with Simple Harmonic motion and Elastic force, but I do not know how to describe it in a more efficient/scientific way. Essentially, I am dropping a weight (constant)...
  21. Prashasti

    Amplitude Modulation of a wave

    Homework Statement I am utterly confused. When I was reading my textbook , I found something unacceptable. While deriving an expression for a modulated wave, It's been given that "A sinusoidal carrier wave can be represented as c (t) = Ac sin (ωt + Φ) where c (t) is the signal strength of...
  22. B

    LRC Series Circuit Voltage amplitude question.

    Homework Statement Hello All, I have a question: In a LRC Series circuit: At what angular frequency is the voltage amplitude across the resistor at a maximum value? At what angular frequency is the voltage amplitude across the inductor at a maximum value? Homework Equations \omega =...
  23. Nathanael

    Is the Amplitude of Sound Waves Constant with Distance?

    A quote from a book: At first, I was under the impression that s_m was constant. But shouldn't s_m be inversely proportional to the distance? The book never says this anywhere directly, but it seems to be implied by two other equations (for the intensity) given in the chapter...
  24. J

    How to find the amplitude of a pendulum

    How do I find the amplitude of a pendulum with the given information: Length=0.5 m Mass=0.25 kg x=0.2 m k (constant)=12.25 N/m Thanks!
  25. R

    Number of amplitudes in one wave cycle

    Homework Statement During one complete cycle, a wave moves through ___ wavelength, ___ period, __ amplitudes Homework EquationsThe Attempt at a Solution Well I got 1 wavelength, 1 period, and 2 amplitudes But apparently the answer is 1 wavelength, 1 period, and 4 amplitudes But I don't see...
  26. S

    Standing waves: can two transverse waves colliding have diff. fq, or amplitude?

    Do all standing waves have to have the same frequency and amplitude?
  27. A

    At what angular frequencies is the amplitude half of its resonant value?

    Homework Statement A simple pendulum has a length of 1m. In free vibration the amplitude of its swings falls off by a factor of e in 50 swings. The pendulum is set into forced vibration by moving its point of suspension horizontally in SHM with an amplitude of 1 mm. a) Built Differential b)...
  28. microsansfil

    "Probabilty amplitude" meaning ?

    Hello, http://en.wikipedia.org/wiki/Probability_amplitude Do you know this concept in the frame of probabilty theory ? If yes what is mathematical sense ? Patrick
  29. A

    Understanding Amplitude and Waveforms

    Homework Statement http://puu.sh/bZQiV/43f7515806.png Homework Equations This is a conceptual conception so no equations[/B]The Attempt at a Solution I believe answer is D since it is the longest and thus can have the highest amplitude. Is it correct?[/B]
  30. C

    Amplitude for scalar-proca couplings

    I'm trying to calculate the amplitude for an interaction between a scalar field $$\phi$$ and two identical spin 1 fields $$A_{\mu} \quad and \quad A^{\mu}$$ for the interaction $$\phi \longrightarrow A^{\mu} A_{\mu}$$ with the Lagrangian density $$L_{int} = -ik\phi A^{\mu} A_{\mu}$$ where k is a...
  31. E

    Amplitude spectrum of signal, power of signal etc

    Hi! Here is my task: 1. Homework Statement Periodic signal is input signal for circuit (photo). a) Calculate and sketch amplitude spectrum of $$u(t+1ms)$$, b) Calculate participation (in percent) of DC component of power of total mean power of signal $$u(t)$$, c) Sketch power spectrum of...
  32. E

    Phase and amplitude spectrum of signal

    Hi! 1. Homework Statement My task is to calculate amplitude and phase spectrum of this signal: Homework Equations My idea is to calculate complex Fourier series of this signal, $$f(t)=\sum_{n=-\infty}^{n=+\infty}Fne^{j\frac{2n\pi t}{T}},$$ where...
  33. R

    Calculating Voltage Amplitude with Faraday's Law

    Farraday's Law states V= -N.flux/time , if this calculates voltage how does one determine amplitude?
  34. ChrisVer

    Amplitude for fermion-fermion Yukawa scattering

    Suppose that we have that: \mathcal{M} = c \bar{u}^{s'}(p') u^s(p) \bar{u}^{r'}(k') u^r(k) For a fermion fermion scattering: f(k,r)+ f(p,s) \rightarrow f(k',r')+ f(p',s') Now if I want to calculate the polarization summed and averaged squared amplitude: \frac{|c|^2}{4} \sum_{r,r',s,s'}...
  35. PsychonautQQ

    Damped shm successive amplitude ratio

    Question: The damped frequency (f) is 100 Hz. The ratio of the amplitude of two successive maxima is one half. What is the undamped frequency? My first problem is I don't understand the basic equations I'm working with. If W is the undamped angular frequency and w is the damped frequency, I...
  36. S

    Why Is Resultant Wave Energy Proportional to Amplitude Difference?

    Homework Statement The energy transferred per second by a progressive waves is directly proportional to the square of amplitude . If two different amplitude waves superpose , the energy per second transferred by the resulatant waves us direcly proportional to (ANS: the diffrence of...
  37. deedsy

    Quantum Wave Function to Momentum Amplitude

    Homework Statement I was hoping someone could verify that I've set up the integral correctly for this problem.. Suppose that at t=0, the wavefunction of a free particle is ψ(x,0) = \sqrt{b} e^{-|x|b + ip_0 x/\hbar} a) what is the momentum amplitude for this wave function? Homework...
  38. L

    How an electromagnetic amplitude becomes QM probability?

    At the core of the quantum concept by Planck was the black-body radiation, then: electromagnetic waves, whose amplitudes are electric and magnetic fields, but when one follow the developments and one comes to the Schrödinger waves, now their amplitudes are not of that kind but related to...
  39. S

    Does Increasing Light Wave Amplitude Mean More Photons?

    If the amplitude of a light wave increases does that mean that the intensity of the wave increases, and thus the number of photons? I'm thinking here re the wave/particle duality of light.
  40. C

    Do AM waves have symmetrical amplitude?

    I've been finding that many videos online depict AM waves (the modulated wave that is transmitted from a circuit/received by your aerial before demodulation) differently. Some show the waves as having symmetric amplitude so at a point (p) on the wave, the voltage is equal to +a and -a. Overall...
  41. C

    The Double Slit Experiment and the amplitude of light

    I just saw a video about the so called "Double Slit Experiment" () which showed that two lightbeams that are parrallel will manipulate each other just like waves in a pond would do. The slits used in this experiment were very close together but you could see them with your eye so I guess they...
  42. A

    Amplitude decrease with geometrical spreading

    Hey, I'm looking at amplitude decrease of a seismic pulse as a result of geometrical spreading. Starting with I = E / (4 * pi * r2) where E = original energy from source, we know that energy falls off as 1/r2, thus amplitude falls off as 1/r. From wikipedia: "The energy or intensity...
  43. B

    History and origin of amplitude summation in QFT

    In chapter 2.2 of Feynman's book on QFT, he states that the probability amplitude of a particle going from a to b is the sum of contributions from all paths, and that each path contributes the same amplitude, but with a different phase. My question is, why does Feynman state that this is the...
  44. D

    Drag the cursor to the the maximum amplitude using LTspice

    Homework Statement So i am trying to find the maximum power transfer of a circuit. See attached image. Is there any way to automatically drag the cursor of a plot to the maximum/minimum amplitude of a signal when simulating LTspice? Or do you need to manually drag the cursor and estimate values...
  45. D

    Amplitude to go from a location to another

    In the Feynman lectures on physics Vol.III (P.3-4), Feynman gives an equation for the amplitude for a free particle of definite energy to go from r1 to r2 to be proportional to \dfrac{e^{ip\cdot r_{12}/\hbar}}{r_{12}}. Where does this equation come from, especially the r12 in the denominator?
  46. H

    Calculating power and energy based on frequency and amplitude (pascal)

    Hello, I'm working on a project to absorb sound energy and I'd like to ask for hints, or methods, of calculating the energy received by the microphone, or energy per second (power). I took measurements using a very sensitive microphone which outputs a voltage to a DAQ card in a PC. Using...
  47. D

    Time taken for the big mass to achieve max amplitude

    Homework Statement the driver is made to oscillate. then the energy will be transferred to the other bob . the other bob oscillate as well all the ball are of the same frequency, as they have the same length. the air resistance is significant for smaller mass bob(paper bob) , so it...
  48. D

    Amplitude of string when the string breaks

    Homework Statement my question is on part b Homework Equations The Attempt at a Solution the period will be shorter due to smaller mass of oscillating system... but the amplitude is greater( ans from my book , in my opinion, the amplitude should be smaller because the string is...
  49. S

    Surface seismic waves and amplitude with distance

    OK so we all know that seismic waves decrease in amplitude at about 1/r, the decay is slower than P and S-waves but it's there. So how do you explain that when I see examples of seismograms of the same earthquake from stations at different distance you can sometimes notice that surface waves...
  50. T

    Why can't amplitude make a tranverse wave faster

    Why is the speed of waves in a medium fixed? I'm trying to conceptualize this, but I can't. I imagine a long piece of chain on the ground, of course made up on individual links. If I yanked on the first link by lifting it up, it wouldn't in act a force on the second link until it made...
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