Amplitude Definition and 825 Threads

My book states: "Power is proportional to amplitude squared" How can this be derived? Thank you!

Webassign night again! Homework Statement During normal conversation, the amplitude of a pressure wave is 0.023 Pa. (a) If the area of the eardrum is 0.56 cm2, what is the force on the eardrum? N (b) The mechanical advantage of the three bones in the middle ear is 1.5. If the force in...

If the momenta on the three external legs p(incoming fermion), p'(outgoing fermion) and p-p' (photon) of a vertex diagram are replaced by -p, -p' and p'-p respectively (i.e., all the external momenta are multiplied by -1) does the amplitude remain unchanged?

The tidal range of spring tides is about 3.2 m and tidal range of neap tides is about 1.8m, Assume the only tidal components are m2 and s2 tides. i.e 2 tides per day due to the sun and moon. Find the amplitude of these components and also find the maximum phase angle between the m2 tides and...

This is not a HW question but an activity i am working on. The attachment is a symbolic AM transmitter. The carrier is 15MHz and message frequency is 2Mhz. I want to sketch the waveforms labelling them in as much detail as possible. Also sketch the output waveform in both time and...

I guess I am just bored, but I was wondering why we assume light travels in a straight line and not treat it like a waveform as I was taught in school. As far as I can remember light waves each have a frequency. Why do we not take into calculation that it actually travels over a longer path...

Homework Statement A mass oscillating on a given spring has a period of 2s. The spring is now stretched to have an oscillation amplitude that is twice its original amplitude. Which of the following is true? A The period is 0.5 s. B The period is 1 s. C The period is 2 s. D The...

A Monochromatic source of light in a vacuum shines light into a block of glass. How does the amplitude of the light wave change once it is inside the glass and once it leaves the glass. I know that some energy (and hence amplitude) is lost by the light wave when it enters the glass due to slight...

If I was to turn up the treble knob on my stereo, is there any effect on the frequency or amplitude of the sound wave?

Homework Statement A mass-spring system has b/m = \omega_0/5 , where b is the damping constant and \omega_0 the natural frequency. How does its amplitude when driven at frequencies 10% above \omega_0 compare with its amplitude at \omega _0 ? How does its amplitude when driven at...

When a string, fixed at both ends, has a force exerted on it, how do you determine what the amplitude will be, if the tension, applied force, and length are known?

Using the following o.d.e L\frac{d^2i}{dt^2}+R\frac{di}{dt}+\frac{1}{C}i=\frac{d}{dt}E(t) The following problem has several parts all of which I have solved except for the one below. L=1/20 R=5 C=4.10^{-4} \frac{dE}{dt}=200\cos100t Where L is an inductance in henries, R is a...

Homework Statement A simple harmonic oscillator has a frequency of 3.4 Hz. It is oscillating along x, where x(t) = A cos(ωt + δ). You are given the velocity at two moments: v(t=0) = 1.8 cm/s and v(t=.1) = -19.3 cm/s. 1)Calculate A. 2)Calculate δ. Homework Equations w= 2pi*f = 21.36 rad/s...

Electirc Field Amplitude Radiation Pattern?? Hi all, How can I calculate the field amplitude radiation pattern of an isotropic antenna? (for the transmitting and receiving case) thanks in advance

When we drag the bob at certen heightand relese it. It start's oscelation. and the the apmlitude of the vibration decreases with time. can anybody help me by giving the equation which tell the decrease in amplitude.

My scenario: LNA 433MHz signal (21dB) from antenna and the difference between the two signals with a 4.1dB gain. I would like to take the result of the difference amplifier an produce a DC value that is proportional to the output. Question 1: What type of circuit would lower the frequency...

I have a question asking for the period, frequency, amplitude and phase angle from simply looking at a graph. I have the period and frequency, and 'think' i have the amplitude (high point - low point / 2), but I don't know how to get the phase angle. No equation is given so I can't simply...

Homework Statement a 200g mass attached to a horizontal spring oscillates at a frequency of 2.0 Hz. At t=0s, the mass is at x=5.0 cm and has v=-30 cm/s. Determine: a) period b)angular frequency c) AMPLITUDE Homework Equations x(t)=Acos(wt+psi) v(t)=-Awsin(wt+psi) w=2*pi*f T=1/f...

I'm learning about radios at the moment but there's a few things I'm not clear about concerning modulation. I'll use audio amplitude modulation as an example. Let's say I have a device which I speak into and this device converts the variations of the sounds waves coming outta my mouth into an...

I hope this is the correct place for my question. I posted it here, because it`s from Peskin & Schroeder: "Consider the amplitude for a free particle to propagate from \mathbf{x}_{0} to \mathbf{x} : U(t)=\left\langle \mathbf{x}\right|e^{-iHt}\left|\mathbf{x_{0}}\right\rangle In...

Am I right in saying that a tapered optical fibre 'collects' light from evanscent field. Why would this mean it needs to oscillate as it scans a sample surface? Cheers! philip

Hello, I am fairly new to quantum physics (I'm actually an engineer, not a physicist). I think I am getting a decent grasp on things, but I have a question. Suppose you have two time dependent states: \Psi_{1} and \Psi_{2}. Also, suppose that we have a constant potential, represented in our...

At what angle of incidence is amplitude coefficient of reflection parallel to the incidence plane 0? my solution is that by Fresnell's equation, r//=tan(i-i`)/tan(i+i`)=0, i=i`,i=90.so for whatever surface,angle of incidence should be 90. is it correct? different from the answer!

A 0.38 kg mass is attached to a spring and executes simple harmonic motion with a period of 0.08 s. The total energy of the system is 1.9 J. Find: a) the force constant of the spring. Answer in units of N/m. b) the amplitude of the motion. Answer in units of m. For a, I got 2341.655 N/m...

Is it possible for a harmonic (produced by a stringed instrument) to have an amplitude higher than the fundamental. If so how?

Is it possible for an object's size to be great enough to make it's wavelength or amplitude < a Planick length? If so, does it's position become certain, and, applying the uncertainty principle, can you not know the velocity?

Hi I hope this is the right place to post. I have some questions regarding EM wave amplitudes. There are some other posts in the past regarding this and some people replied by saying that amplitude of a light wave is equal/close to wavelength of the wave. This is deduced from the fact that...

Homework Statement A loudspeaker of 30cm diameter vibrates at 2kHz. Given that the pressure generated is 55.1N/m2, determine the displaced amplitude. Assume air density is 1.59kg/m3 and that the speed of sound is 340m/s. I have been told that the dimensions given for the loadspeaker is...

How can one determine the amplitude, frequency and period of an amplitude? this is not homework, i was just curious, because i knew how to find the time using the 2 pi sqrt(l/g), but wanted to know about this, since i am learning about waves and harmonic motion! Help would be appreciated...

Which one of the following statements about an oscillating mechanical system at resonance, when it oscillates with a constant amplitude, is not correct? A The amplitude of oscillations depends on the amount of damping. B The frequency of the applied force is the same as the natural frequency...

Homework Statement An experiment to monitor the sound level in a room is to be conducted using a microphone. The microphone (output impedance = 1 kO) produces a maximum amplitude of 5 mV when connected to an oscilloscope (input impedance = 1 MO). If RI = 1 kO what amplitude will the...

Homework Statement Hi all. I have the following harmonic function: V(t)=A\cos(\omega t)\exp(-Ct), where C is a constant, and A is the amplitude. I need to find the time t, where the amplitude is A/2. This gives me: V(t)=A\cos(\omega t)\exp(-Ct) = \frac{A}{2}, but how...

How come the energy of an electromagnetic wave depends only on its frequency? Given by E = hf. How come the energy depends only on the frequency of the wave and not on the magnitude of the E component of the wave? Doesn't the energy depend on the amplitude? Or is there no such thing?

Hello, I've found different formulas regarding wave energy. 1) Wave energy is proportional to wave length \lambda times wave height squared 2) Wave energy is proportional to wave period T times wave amplitude squared From what I've read, wave period is equivalent to wave length. But...

Homework Statement A 100 g ball is attached to a spring with spring constant 2.5 N/m oscillates horizontally on a frictionless table. Its velocity is 20 cm/s when x = -5.0 cm. What is the amplitude of the oscillation? Homework Equations x = Acos(ωt +φ ) V= -ωAcos(ωt +φ ) The...

Homework Statement A 2.0 m long string vibrates at its second harmonic frequency with a maximum amplitude of 2.0cm. One end of the string is at x = 0cm. Find the oscillation amplitude at x = 10,20,30,40, and 50cm. Homework Equations A(x) = 2asin(kx) k= 2pi/wavelength The Attempt at...

Homework Statement Hi all. Please take a look at the attached circuit. I've have found the amplitude of the current through the resistance to be: \left| {I_0 } \right| = \frac{{\varepsilon _0 }}{{\left| {R - \frac{R}{{\omega ^2 LC}} + \frac{i}{{\omega C}}} \right|}}, where ε_0 is the...

[SOLVED] Finding the Amplitude of a spring (Simple Harmonic Motion) First post here at PF, so forgive me if I make a faux pas. I'm trying to study for an upcoming Physics test and I'm having a bit of trouble with this. Homework Statement A massless spring with spring constant 19 N/m hangs...

Homework Statement The eigenstates of two commuting operators A and B are denoted |a,b> and satisfy the eigenvalue equations A|a,b>=a|a,b> and B|a,b>=b|a,b>. A system is set up in the state |psi> = N(|1,2> + |2,2> + |1,3>) What is the value of the normalization constant N? A...

A book is placed on a horizontal wooden plane that is undergoing simple harmonic motion with an amplitude of 1.0 m. The coefficiet of friction btween the book and the horizontal wooden plane is given by μ = 0.5. Determine the frequebcy of the horizontal wooden platform when the book is about...

Homework Statement A 200 g ball attached to a spring with spring constant 2.50 N/m oscillates horizontally on a frictionless table. Its velocity is 18.0 cm/s when x = -5.00 cm. A. What is the amplitude of oscillation? B. What is the speed of the ball when x = 3.00 cm? Homework Equations A...

I've run an experiment on an active filter. I am using the NI Elvis prototyping board. The frequency response is taken with the NI Bode analyzer and I saved the output data in a text file. The Bode analyzer amplitude spec is give as 12 or 16 bits, how do I calculate the amplitude error using the...

Homework Statement A large block with mass 30 kg executes horizontal simple harmonic motion as it slides across a frictionless surface with a frequency of .75 Hz. A smaller block with mass 10 kg rests on it, as shown in the figure, and the coefficient of static friction between the two is...

Homework Statement You are finding it a challenge to climb from one boat up onto a higher boat in heavy waves. If the climb varies from 2.1 m to 4.5m , what is the amplitude of the wave? Assume the centers of the two boats are a half wavelength apart. Homework Equations just used...

* A 200g block attached to a horizontal spring is oscillating with an amplitude of 3 cm and a frequency of 2 Hz. Just as it passes through the equilibrium point a shalock so trp blow exerts a force impulse on the that the speed of the block is increased by .5m/s. What are the new a) frequency...

when does amplitude start affecting the period of the pendulum? I know large amplitudes do.. and I've tried looking it up but none of the equations out there make sense.. :S

Homework Statement A car is moving along a hill at constant speed on an undulating road with profile h(x) where h'(x) is small. The car is represented by a chassis which keeps contact with the road , connected to an upper mass m by a spring and a damper. At time t, the upper mas has...

Homework Statement What is the pressure amplitude in sound wave with intensity level of 65 dB? The Attempt at a Solution My textbook does not provide any instruction on how pressure amplitude is related to the intensity level. It does not even define what pressure amplitude is. While I...

Does anyone know a deeper reason why the quantum mechanical probability amplitude has to be complex? Is it to incorperate time dependence? Or maybe the operator/eigenvector formulation is special and since it includes the scalar product, having complex variables is more general and...

Energy and Amplitude of Oscillation An atom in a crystal lattice can be regarded as having a mass of 2.0E-26 kg attched to a spring. The frequency of this oscillator is 1.0E13 Hz. What is the amplitude of oscillation if the energy of oscillation is one energy quantum? I know E=nhv, here n=1...