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Zohar Komargodski in these lecture notes claims:
I don't understand the requirement about unitarity.
Why must residues be expressed in terms of Legendre polynomials?
How does this statement follow from unitarity?
|
As the title says, how would I obtain the vector $\mathbf t$ if the vector $\mathbf i$ and the refractive indices are known? I've tried for hours but I keep getting stuck. Is there an equation readily available?
Thank you.
|
I came up with this idea today and am just wondering if it is feasible. It is much easier to communicate via images so I drew the attached image to convey it. The key concept is rolling a ball in order to get water back up to the top so that it can fall back down through a turbine again and again just using gravity. Wh... |
When I check classical electromagnetism books Maxwell equations
\begin{equation}
\Box A^\nu (x)=\frac{4\pi}{c}j^\nu (x)
\end{equation}
can be solved using a scalar Green function $G(x,x')$
\begin{equation}
A^\nu (x)=\int G(x,x')j^\nu (x')d^4x'
\end{equation}
where the Green function satisfies
\begin{equation}
\Box G(x,... |
TL;DR
Need to make a graph which showcases all parameters of a PMDC motor against the torque input.
I am trying create a graph similar to as shown below. However, I am confused as to how the torque is related to the characteristics.
The graph that is to be replicated for certain parameters:
The parameters that I have ... |
There are many electrons in a wire. When current flows in the wire, the electrons move in the wire with a very high velocity. Will it increase the mass of the wire due to Special Relativity?
|
We define the norm of the operator as $\left\lVert A \right\rVert = \sup \frac{\left\lVert A\psi \right\rVert}{ \left\lVert A \right\rVert} = \sup \left\lVert A\psi \right\rVert$ for $A ∈ L(H)$. It is said that $||A||$ measures the magnitude of the action of $A$.
What is meant by the action of $A$ and what is sup in t... |
I’m currently studying quantum mechanics from Introduction to Quantum Mechanics by Griffiths. In his free particle section, he says that the speed of a particle is the coefficient of $t$ over the coefficient of $x$. Shouldn’t it be the coefficient of $x$ over the coefficient of $t$?
|
Let me start with an example. If one considers a free particle motion on two-dimensional plane and projects it onto the radial coordinate, one gets the following Hamiltonian
$$H = \frac{p^2}{2}+g^2 \frac{1}{ q^2}$$
which is integrable (and known as a one-particle rational Calogero model). Considering free motions on sp... |
The wave impedance is given by
${\displaystyle Z={E_{0}^{-}(x) \over H_{0}^{-}(x)}}$
where
${\displaystyle E_{0}^{-}(x)}$ is the electric field and ${\displaystyle H_{0}^{-}(x)} $ is the magnetic field, in phasor representation. The impedance is, in general, a complex number.
On Wikipedia's article, it mentions 'phasor... |
We can set up a light filter and a light source such that angling the filter may block out some/all of the light. For example, with a certain filter angle we might see that $30\%$ of the original light passes through the filter, with the filter blocking the remaining $70\%$.
But if we send a single photon out from that... |
I'm trying to figure out how to apply the radiative transfer model to calculate the brightness temperature Tb in microwave (Rayleigh–Jeans approximation) considering atmosphere and no scattering.
If I had a radiometer at the ground pointed upward perfectly vertical, in several papers I found that I can calculate Tb by:... |
I am following Das' Finite Temperature Field Theory and the discussion of the effective potential. Das defines,
\begin{equation}
S^J
=
\int d^4x
\left[
\frac{1}{2}\partial^\mu\phi\partial_\mu\phi - \frac{1}{2}m^2\phi^2 - \frac{\lambda}{4!}\phi^4 + J\phi
\right]
=
S + \int d^4x\ J\phi.
\end{equation}
The generating func... |
Can someone give a review of good books to learn semiclassical physics? Somehow, I would like to know if there is a text at the level of Lanczos or Gelfand. By this, I mean that I am interested in the combination of semiclassical physics with variational problems in the context of QFT (with the variational problems at ... |
Some force are applied in a moment, some force are applied continuously and forever without any break in continuity. What's the opposite of that? Is there a qualifier for that? I was thinking discrete as in discrete mathematics, but discrete relates to things and not how they relate to time in a "discrete" way.
|
The boundary conditions for an electromagnetic wave passing from one linear dielectric media to the other (both having no free charges or current) are taken as:
$$B_{\perp_1} -B_{\perp_2} =0$$
$${\varepsilon_1} \cdot E_{\perp_1} -{\varepsilon_2}\cdot E_{\perp_2} =0$$
$$\frac{B_{||_1}} {\mu_1}-\frac{B_{||_2}}{\mu_2} = 0... |
It is correct to say that the instruments that measure signal have a large impedance as opposed to the instruments that generate signal, whose impedance turns out to be small.
I know that this is true of many laboratory equipment but can we generalize it as I explained before?
I really appreciate your time.
|
The above figure shows how the regular-solution free energy might lead to liquid–liquid equilibrium. In the region between the compositions $x^I_A$ and $x^{II}_A$, $G$ increases with $x_A$. If the overall concentration lies between these two values, it is always favorable for the
system to spontaneously phase-separate... |
There can be never two fermions in exactly the same state,
which is known as Pauli’s exclusion principle, but infinitely many
bosons.
I read in the book saying that if Pauli's exclusion principle does not exist (that means not valid), matter will not exist. But I don't get that point why? Can someone explain this fact?... |
Suppose there is a container (filled with vacuum) in which there is a particle (only one).Let the initial temperature be $0K$ so that the particle will have $0$ Thermal energy. Now as we increase the temperature the particle will start to accelerate from rest. I searched the internet and my book which points out that t... |
To find the shear stress at point A in the beam above using the equation τ=VQ/(It), how do you decide which value of thickness to use? Is it correct to use a value of 100 mm because the cut segment at A is 100 mm long , or 20 mm because the segment extends to both ends of the beam and so the shear stress at A acts at ... |
As we have developed the idea of electric field lines from Coulomb's law. If two equal and opposite charges are in plane, all the effect of electric field vectors adds to line joining the two points, which means all the electric field lines of forces contribute to Coulomb's force.
When more than two charges are in plan... |
The density of electron states in a 3D semiconductor is given by $\rho(E)=\frac{1}{2\pi^2}\left(\frac{2 m^*}{\hbar^2}\right)^{3/2}\sqrt{E}$, derived commonly as shown here. I'm trying to understand how to set $E$ when I'm counting states, thinking in terms of a band diagram like this one.
If I'm counting the number of... |
First law of motion clearly says that, anything that creates a state change is a force.
So, in our thermodynamic systems thermal energy, hence kinetic energy of constituent particles change when temperature is correspondingly changed. Change in kinetic energy means change in velocity, hence acceleration. So, is tempera... |
How is the Rapidity Vector calculated from Velocity Vector in 3-D and vice versa in Special Relativity?
What I want is to take 2 3D Velocity Vectors, convert each to corresponding 3D Rapidity Vectors, Add them and Covert the resultant 3D Rapidity Vector Back to 3D Velocity Vector. Verify that Velocity Vector thus obtai... |
I am currently studying material science and we had been going through strengthening lately. One thing I never thoroughly understand is how exactly does point defects such as vacancies and interstitial defects relates with dislocation motion. On macroscopic scale, it is visible that the dislocation motion is halted by ... |
Consider a two-level system described by the hamiltonian
$H = \hbar \omega_{eg} /2 \sigma_z \quad (1)$
The eigenenergies are $\pm \hbar \omega_{eg}/2$. Now, we add an interaction with an electromagnetic field, e.g.
$H = \hbar \omega_{eg} /2 \sigma_z - \vec{d} \cdot \vec{E}$.
The Hamiltonian can be transformed into the ... |
I am calculating the cross-section for quark gluon to quark gluon scattering in the spinor helicity formalism. This process has contributions from the Mandelstam channels $s$, $t$ and $u$.
Using the usual brute-force Feynman calculus, I obtain for the average over initial and sum over final states for the $u$-channel
\... |
I'm a little confused with this high-school mechanics question. Where you have two spring with different spring constants, say $k_1$ and $k_2$, we joint them together and of the resultant spring, one end is attached to the mass and the other to a fixed end.
Now the equation of motion of the mass will be given by
$$\f... |
Does moment of inertia have a direction or is it just a property?
|
Molecules are the result of covalent bonds forming between atoms.
Which of the four fundamental forces is responsible for covalent bonding?
(Sorry if this is basic -- I'm guessing electromagnetic, but just wanted to check.)
|
In this question, I am unable to understand why charge would pile up at the junction in the first place. This is current electricity, not electrostatics, and the current is same through both the materials, obviously. So, the charge flowing in would be the same as the charge flowing out. Where am I going wrong with thi... |
I'm new here, possibly my apologies for misplacing.
After a measurement in quantum mechanics, the wavefunction collapses to an eigenstate corresponding to the outcome of the measurement. Thus if we want to apply this to the momentum observable, the outcome of the impulse can be random, but after the measurement, we kno... |
What can we deduce about an ion, its interaction or the structure it is in, based on the ionic radius?
My understanding of the concept of the ionic radius is that these are seen almost as having a physical hard shell, but what does that truly mean?
Is it a way of picturing the distance up to which they can interact wit... |
I am studying the potential electric of a sodium chloride crystal, where the actors says:
To evaluate the potential energy we first observe that every positive
ion is in a position equivalent to that of every other positive ion. Furthermore,
although it is perhaps not immediately obvious from Fig. 1.7, the
arrangement... |
For example, if wire $A$ has diameter $D$ and length $L$ when a force of $4N$ is applied, it extends to let's say, $0.8mm$.
Another wire $B$ has length and diameter $2L$ and $2D$ respectively. Now, will the extension be greater or lower?
By the way, both wires obey Hooke's law and are identical except for their dimensi... |
Suppose we have the following situation and I'm asked for the minimal speed to be given to the ball so it can continue a full cycle.
If the ball is connected to the middle point with some hard material (like Iron) then the answer is: $v_{min}=\sqrt{4gh}$ (using the law of conservation of energy we calculate the minimu... |
I'm stuck for some days trying to get the diffraction pattern from a binary grating / square period grating / multi-aperture square screen... whatever you want to call it.
Imagine I have a 8 * 5 square apertures grating. Something like this:
The intensity profile from a single aperture is easy to calculate:
% Clean a... |
So let's say power to be delivered to homes is 80 kW($P_3$ = 80 kW) and the houses have to receive it at 220 V ($V_3$ = 220 V). The substation is a 4000 V to 220 V step-down transformer and $R_2=15\ \Omega$.
It says that the power loss is $I^2R$, and I understand that here it has to be $I_2^2R_2$. But I'm confused abo... |
I am trying to verify that the following equation is true:
$$(\vec{\sigma}\cdot\vec{p}) (\vec{\sigma}\cdot\vec{p}) = (\vec{\sigma}\cdot\vec{p}) p^0$$ where $p^\mu=(p^0,\vec{p})$ is the four momentum operator and $\vec{\sigma}$ is the Pauli matrices vector. This equation was taken from Ashok Das' QFT book, pg 96, eq. 3.... |
I am going through the BRST quantisation in Perturbative quantum gravity and looked at the papers of Nishijima and Ojima. I am confused about the closure of the BRST operator; I.e $s^2=0$, particularly in the case of the ghost field.
The BRST transform of the ghost field is:
$$sc^{\mu} = c^{\lambda}\nabla_{\lambda}c^{... |
I saw a video explaining the central fringe width of a single slit diffraction pattern with the uncertainty principle. It explained: as the slit size decreases, the uncertainty of the position of photons decreases, so the uncertainty of the momentum of photons increases, and thus the fringe width increases. This made m... |
I'm working on a coil - iron system analyze project
A problem that I faced with is effect of movements of the iron on the coil current & force
I want to analyze force of the coil on iron block in a situation that Coil is pulling the iron block and iron block is moving to coil center
so we know the coil did some work an... |
To derive kinetic energy expression for a rolling body, we consider the instantaneous center of rotation and write the angular energy about that point. After some algebraic simplification, we conclude at:
$$ K =\frac{1}{2} (I_C + MR^2) \omega^2 \tag{1}$$
Where $ I_c$ is the inertia of the body about the center of mass,... |
Below is the diagram (sorry for bad accuracy) that shows how current changes with time in LC circuit. On X-axis we have time measured in milliseconds (ms) and on Y-axis current measured in milliamperes (mA). I know that inductance in this circuit is 20mH and I'm trying to calculate capacitance but however I try, my sol... |
If gravitons mediate the gravitational force, couldn’t the detection of gravitons by an observer be used to distinguish whether they are experiencing gravitational acceleration vs. inertial acceleration, contradictory to general relativity? If this is not the case, and detection of gravitons can not be used to distingu... |
I'm a physics grad student interested in pursuing physics in a mathematically rigorous manner. However, I've hit a roadblock with the two volume book, Quantum Fields and Strings: A Course For Mathematicians by Deligne, et. Al.
I have covered enough Differential Geometry, Group Theory, Representation Theory and Function... |
Say the real part of
$$\tilde{\mathbf{E}}(z, t)=\tilde{\mathbf{E}}_{0} e^{i(k z-\omega t)}$$
satisfies all Maxwell's equations. Then how can we say the imaginary part satisfies the equations as well?
Griffiths says in a footnote
Because the real part of E differs from the imaginary part only in the replacement of sine... |
I do not understand the relation between the determinant of the metric tensor $g$ and the non-tensorial symbol $\tilde{\epsilon}_{\mu_{0}..\mu_{n}}$. This is explained in Carrol's book as followed:
\begin{equation}
\tilde{\epsilon}_{\bar{\mu}_{0}..\bar{\mu}_{n}}| M|=\tilde{\epsilon}_{\mu_{0}..\mu_{n}}M^{\mu_{0}}_{\ \ \... |
I have two coupled oscillators, namely a particle in an ion trap and an RLC circuit. The particle oscillates in this ion trap and induces charges in the RLC circuit, in turn the RLC circuit's voltage oscillates and drives the particle. Energy is dissipated via the resistor in the RLC circuit and at the same time added ... |
I was wondering if someone might be able to explain how you could determine what the basis vectors would be for a decorated square lattice otherwise known as a square kagome (squagome lattice)? My initial thought was that it would be [sqrt(2),sqrt(2)] but now I am not sure.
|
Question:
Without calculation, state what happens, if anything, to the reading of ammeter $A1$ if:
The $2 \ \Omega$ resistor $R1$ is shorted out with a thick piece of wire
The piece of wire is removed and the $3 \ \Omega$ resistor $R3$ is removed
Answers:
Stays the same
Decreases
I'm new to circuits and I d... |
Hello I'm having trouble setting up the correct form of the Maxwell-Faraday law to help me find the induced current density on a disk in an alternating magnetic field. The problem is set out as follows:
A thin conducting disk of thickness h, diameter D, and conductivity σ is placed in a uniform magnetic field $B = B_{0... |
If we could transfer energy wirelessly with 100% at short range. I think we could then use the energy to power an electromagnet from the stator side. So we wouldn't need a permanent magnet at all but I think it would still gain the same torque and efficiency as a conventional magnet motor.
But I can't find anyone who d... |
When light is directed towards our eyes we detect the source and locate it. In Huygens' principle it is said that every point on wavefront acts as a source of secondary waves which again travel in all possible directions.
If light is directed not towards our eyes, like path of eyesight being perpendicular to path of li... |
According to pythagorean theorem V2 should be greater then V1.But why doesn't it happen?
|
So, I'm reading through Polyakov's paper from 1974, "Particle Spectrum in Quantum Field Theory." I'm trying to work through all of the steps and properly understand everything. For context, this is one of the papers along with 't Hooft's that the name 't Hooft-Polyakov monopoles came from. The paper starts out with the... |
If we consider the Potential and electric field of a Dipole,
could we infer that for a dipole :
$V \propto 1/r^2$, $E \propto 1/r^3$ , $da \propto r^2$, then
Electrostatic potential energy should vary as $\propto 1/r^3$.
Basically I want know whether the energy term also varies as accordingly for dipole , quadrupole .... |
I have these following two experiments that seemed not so clear for me
Michelson Morley experiment -
The first one is the experiment from Michelson and Morley who proved (if I'm not wrong) that the speed of light is constant no matter what the speed of the observer is by using an interferometer. I'm not sure if the fo... |
Could anyone recommend a source where they prove or explain the following claim at an undergraduate level?
"More generally, it follows immediately from the properties of Hermitian eigensystems that the eigenvalues minimize a variational problem."
|
Assume I’m given a standing wave function and I’m asked to find the phase velocity of the two waves that interfered and created the standing wave.
Now, I have two questions:
Is it possible to move faster than the phase velocity?
Is it possible that the phase velocity is bigger than light velocity?
I just started to... |
In the book "A first course of General Relativity" by Schutz I am stuck in trying to calculate Christoffel's symbols for an exact plane wave. I have the metric:
$$ds^2 = -dudv+f^2(u)dx^2+g^2(u)dy^2$$
from which I think I get $g_{uv}=g_{vu}=-1/2$ , $g_{xx}=f^2(u)$ and $g_{yy}=g^2(u)$.
So, in order to calculate $\Gamma^x... |
The electroweak force separated into the weak force and electromagnetism. So, will the electromagnetic force eventually separate into electricity and magnetism?
|
Simple question about some mathematical syntax in Zee's QFT book, page 49. I have the generating functional
$$
Z=\int\!D\varphi\,\exp\left\{ i\int\!d^4x\,\frac{1}{2}\big[ (\partial\varphi)^2-m^2\varphi^2 \big] -\frac{\lambda}{4!}\varphi^4+J\varphi \right\},$$
which I want to expand in powers of $\lambda$. Obviousl... |
I am thinking of two circular gears with radii $R_1$ and $R_2=2R_1$. Gear 1 initially spins at $\Omega_1=10$ $rpm$ while the Gear 2 is at rest. After the gears come into contact, Gear 2 angularly accelerates and eventually reaches the steady speed $\Omega_2=20$ $rpm$.
Gear 1 applies a torque $\tau_1=F_1 R_1$ on the sec... |
In page 380 of Nielsen and Chuang (Quantum information), there's a statement about the amplitude damping channel, which is defined by the operators $E_0 = \begin{bmatrix}1 & 0\\0 & \sqrt{1-\lambda}\end{bmatrix}$ and $E_1 = \begin{bmatrix}0 & \sqrt{\lambda}\\0 & 0\end{bmatrix}$ where $\lambda$ can be interpreted as the ... |
I am trying to write an implementation of the discrete Fourier transform myself in Python, but for some reason, the transform that I get out is wrong. There are no fancy tricks in my implementation, I just directly took the discrete formula for a Fourier transform:
$$
X_k = \sum^{N-1}_{n=0} x_n \cdot e^{-\frac{i 2 \pi}... |
If I got it right, the buoyancy force is a result of pressure changes exerted by the gravitational force. Archimedes’ law then generally predicts the buoyant force to be $\rho_\text{fluid} Vg$. What I fail to understand is why when I calculate the total force due to pressure around a sphere of radius $R$ for example, I... |
Essentially, I'm using CMS Dimuon data, from the decay of a $J/\psi$ particle, to prove that momentum is 'conserved' in relativistic collisions. However, I'm unable to find how I can do this. I thought of using the Dispersion Relation formula which is $E^2 = p^2 + mc^2$ but I'm not sure how I'd apply it to the data. I ... |
Could one say that spontaneous emission is expected from thermodynamics, as a isolated atom needs a relaxation process to the ground state to reach equilibrium at low temperatures?
|
When you open the door of your spaceship, the oxygen disappears from the ship.
So if I put a very very long tube from the Earth to space,
would all the oxygen from the Earth automatically aspire into space?
And then no one can breathe anymore so everyone dies.
|
For a system of two particles, we often let the potential energy for the force between the particles approach zero as the separation of the particles approaches infinity. If this choice is made, why the potential energy at non-infinite separation is positive if the particles repel one another and negative if they attra... |
I've been going through Feynman's lectures. One thing he said, unless I misunderstood, is that the temperature of a gas molecule is determined by its velocity, but not its vibration or rotation.
Did I get that wrong? It seems that a molecule hitting the wall of a vessel would impart more energy if it was spinning.
|
We know that there is no frame in which the energy of a photon is zero and hence it has zero momentum.
But can we find a frame in which the energy of two head on photons is zero, or the center of mass frame for two head on collision photons having different energies?
|
I am informed that a system of even number of fermions has integer spin. I don't know how to show it with creation and annihilation operators.
|
For long-range barrier tunneling, consider three qubits governed by the Hamiltonian $H$.
$$
H = -J(\sigma_1^+\sigma_2^-+\sigma_1^-\sigma_2^++\sigma_3^+\sigma_2^-+\sigma_3^-\sigma_2^+)+\frac{U}2\sigma^z_2, \ \text{for} \ J \ll U
$$
How do we modify it so that there are $L$ high-energy sites between two endpoints such as... |
I am starting from the assumption that the gravitational warping of spacetime increases its volume, so a spherical region of space with a fixed surface area would be able to fit a larger number of telephone booths inside it if it contained a large mass than it would without the mass. John Rennie's answer to this questi... |
In Torquato's Random Heterogeneous Materials, he has written
$$\frac{p}{\rho kT} = 1+2^{d-1}\eta g_2 (D^{+})$$
where $g_2(D^+)$ is the contact value from the right-side of the radial distribution function, and $\eta$ is a dimensionless reduced density.
After a couple lines, he states that for hard spheres, via the Orns... |
When a ray of light coming from the medium $n_1$
$\mbox{ has an incident angle } \theta_1 = \theta_c$
where $\theta_c = \mbox{critical angle}$
what phenomenon are we observing? Is it called a partial internal reflection? In others, is only some of the light reflected back into the medium? What about the rest?
|
I studied the formula that to calculate the wavelength of a matter wave we have to calculate $h/p$ where $h$ is plancks constant and $p$ is the momentum of the particle for which we want to calculate the wave length
wikipedia-link: https://en.wikipedia.org/wiki/Matter_wave. And I am wondering how to calculate the ampli... |
"The RC circuit averages past history at the input with a weighting factor of e−Δt/RC."
|
I‘m curios about the verification of the Huygens-Fresnel principle for light. For water it is clear visible in experiments, that the wave behind an opening disperses out all over 180°.
For light the same is claimed, like we see it in the sketch, I took from ad2004s answer to another question.
With naked eye, I‘m not a... |
Can i find the moment of inertia at P if the axis is XX'(passes through the COM) or is the moment of inertia same at every point ???
|
I'm a high school student and I am really confused about a point from rotational mechanics.
My confusion is as follows-
We are often taught that $\tau=dL/dt$ and $\tau=I\alpha$ are the same if the moment of inertia is constant about an axis, but my problem is that when I apply $\tau=dL/dt$ to solve any problem, I can ... |
Being a high school student, I read the concept of center of mass and it was written in my book that
When a spinning ball is projected with some velocity , then all the points on the ball have complicated paths except the center of that ball which follows the well known parabolic trajectory. And hence we define that p... |
In Mark Srednicki's QFT book, section $5$, he mentions following things:
$a^{\dagger}({\bf k})$ creates a particle with momentum $k$ and is given by
\begin{equation}
a^{\dagger}(k)=-i\int d^3x [e^{ikx}\partial_{0}\phi(x)-\phi(x)\partial_0(e^{ikx})].\tag{5.2}
\end{equation}
In the next, he defines another operator $a_1^... |
How to determine initial permeability of the sample having only its dimensions (ring with $R$ - external radius, $r$ - internal radius, and thickness $h$), the number of coils around it $N$, and only information about voltage, that it comes from oscillator level of $0.5V$. All of these are supported by experimental dat... |
From what I understand, if we develop the terms in the Lagrangian of SM containing the $SU(2)$ quark doublets
$$Q_{i,L}=\begin{pmatrix}
u_{i,L}\\
d_{i,L}
\end{pmatrix}$$
with $u_i=u,c,t$ and $d_i=d,s,b$, the terms that are responsible for the mass of the quarks mixes different quarks together. We then say this doesn't ... |
Consider a chain of mass $m$ whose one end is lifted upwards to a height $h$. The work done in this case would be $$\frac{mgh}{2}$$ But I didn't quite get why $mgh$ is divided by $2$. When I looked this up on the internet, it said that when objects like ladders, chains et cetera are lifted from one end, to calculate wo... |
I know that electromagnetic wave consists of electric field and magnetic field, say:
$ \overrightarrow{E}\left(x,t\right)=E_{0}\cos\left(kx-\omega t\right) $
$ \overrightarrow{B}\left(z,t\right)=B_{o}\cos\left(kz-wt\right) $
But if I want to represent the wave consists of both fields as one equation, should I just add ... |
I was conducting an experiment to see if my sink faucet is flammable. I did this by putting a lighter near a running facet. My first guess was that the flame will go out because of the water. But I slowly realized the actual source has to be wet not the flame itself. But I noticed something else that was weird. When I ... |
Consider the question from this post where I had asked about a scenario where a pendulum was attached to the roof of a car and I wished to understand how people in different frames would understand the same behavior of the pendulum.
The person outside understands the pendulum as initially staying in place but then is d... |
If the ear is phase insensitive (Ohm’s Law of acoustics), and you listen on headphones, how can the brain hear a phase inversion on one channel of a stereo signal?
I play bass guitar and practice on stereo headphones. With a split mono signal, it centred exactly between my ears. Experimenting, I inverted one channel, ... |
When solving the problems of V. Rubakov's "Classical Theory of Gauge fields" book, I encountered the following phenomenon:
For a real scalar fields (spin 0) $\phi$, if we consider the action with source $\rho(\overrightarrow{x},t)$,
$$S=\int d^4x \left\{ \frac{1}{2}\partial_\mu\phi\partial^\mu\phi-\frac{m^2}{2}\phi^2+... |
I have done many problems where where a small body is thrown from a moving cart and we have to use conservation of momentum to find the final velocities of the cart and the thrown object. To find the velocity of the thrown body with respect to the ground frame, we have to add the velocity with which it is thrown and ve... |
The inner product of acceleration and speed is (the product of) both their moduli times the cosine of the angle between them, which divided by speed leaves the acceleration (modulus) times the cosine. Then the above statement is true only if velocity and acceleration are parallel which is not true in general.
|
Above this sentence is an image of the diagram and paragraph I have been reading about polarization via scattering.
Question:
Light EM waves are transverse waves aka move perpendicular to the direction they are traveling. There can be no polarization in the scattered light parallel to the original ray because that wo... |
Why must the term $kx-\omega t$ be constant? I mean from an intuitive point of view.
I can mathematically prove it, however I don't seem to understand it very well.
|
original problem
Two ships A And B originally at a distance $d$ from each other depart at the same time from a straight coastline. Ship Moves along a straight line perpendicular to the shore while ship B constantly heads for ship A having at each moment the same speed as the latter. After a sufficiently great interval ... |
Can anyone please provide me with an example of unperturbed Hamiltonian for a certain physical system, which has no time-reversal symmetry, the only condition is that the spectrum of unperturbed Hamiltonian must be well known? Also then please provide me with an example of perturbation for this specific case, for which... |
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