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In classical mechanics text, when learning about Poisson brackets, one gets
$\frac{df}{dt} = \{f,H\} +\frac{\partial f}{\partial t}$, where $H$ is the Hamiltonian of the system and for $\frac{df}{dt}=0$, $f$ is a constant of motion. It is taught that if there is no explicit time-dependence in $f$, then $\{f,H\}=0$.
How... |
In Star Wars 3 in the initial crash scene where a spaceship enters the atmosphere for an emergency landing the thrust engine is blocked by a part of the ship and absorbs a part of the thrust which suggests that it's used as a brake.
I'd be interested if that could work inside or outside an atmosphere. However I have fe... |
$\int dq / T$ of system + $\int dq / T$of surrounding >0 Should always be greater than 0 is the statement in my book for 2nd law of thermodynamics.
And that $\Delta S$ of system + $\Delta S$ of surrounding >0.
My question is:
If there is a container and adiabatic process is happening.Then $\Delta S$ of system + $\D... |
Question is essentially: How can the states on a quantum dot be bound when we can tunnel onto them? If plane wave states can tunnel onto them, these plane waves states and the 'bound' states will have the same energy. Thus we could find a state containing plane waves on either side of the dot and the 'bound' state. So ... |
While the inflation phase of the universe, expansion was exponential and so the universe was de Sitter-like. So, for a point-like observer, there was a cosmological event horizon. Do this horizon evaporates due to the emission of particles? If this horizon evaporates does this mean that the expansion tends to be natura... |
In Griffiths' Introduction to Electrodynamics, 4th ed., he motivates the notion of capacitance by arguing that the electric field $\bar{E}$ is proportional to the charge, and hence so is the potential $V$; the constant of proportionality being the capacitance $C$.
Now, the electric field for a charge distribution is de... |
I calculated the following the integrals:
$$\langle 100|\hat{\overline{r}}|100 \rangle=0$$
$$\langle100|\hat{\overline{r}}|200\rangle=0$$
$$\langle100|\hat{\overline{r}}|210\rangle=\frac{128\sqrt{2}a_{0}}{243}\hat{k}$$
$$\langle100|\hat{\overline{r}}|211\rangle=\frac{-128a_{0}}{243}\hat{i}-\frac{i128a_{0}}{243}\hat{j}$... |
Why isn't the direction of magnetic field all around the electric field( in circles) in an electromagnetic wave? (Instead it is shown only in a single direction in the diagrams)
|
I have studied General Relativity and there is one thing that I have trouble comprehending.
What does local really mean? I will give some examples:
The Hessian
The Hessian is a way to compute the local curvature of a function. What does local mean in this case? At a small area that is not infinitesimally small or an in... |
Einstein's equation in absense of any source (i.e., $T_{ab}=0$) $$R_{ab}-\frac{1}{2}g_{ab}R=0$$ has the solution $$R_{ab}=0.$$
But I think $R_{ab}=0$ does not imply that all components of the Riemann-Christoffel curvature tensor $R^c_{dab}$ be zero (or does it?). From this can I conclude that spacetime can be curved ev... |
I'm confused about why the boiling of liquids happen. The boiling point of a liquid is defined as the temperature in which it's vapor pressure is equal to the pressure of the gas above the liquid( for example the atmospheric pressure ), and vapor pressure is defined as the (temperature dependent) partial pressure of th... |
If the gravity of a star can change the trajectory of a photon, is the speed of the photon reduced at the moment of departure from the stellar's surface? Can modern science calculate the measure of change?
|
Hi I am currently studying Bragg wiliam theory and I dont understand how they derive the equations f(T,m). Actually i dont understand how they got S/N given by equation 8. Can someone explain?
|
I got confused on the calculation of chiral condensate in David Tong's Gauge theory. The equation 3.52 reads
\begin{equation}
\langle\bar{\psi}_{-}\psi_{+}\rangle=\big(\prod_{n}\lambda_n\big)\frac{1}{2}\big(\sum_{l}\frac{1}{\lambda_l}\bar{\phi}_l(1+\gamma^5)\phi_l\big),\tag{3.52}
\end{equation}
where $\phi_l$'s are eig... |
I've seen some interesting analogies explaining why exactly Work and Heat are path function. One where the floors of a building describe the gravitational potential energy, while stairs and elevator are the two paths one can take to reach between the two states of energy.
But my question is how would the same analogy a... |
I've attached a fairly benign example from the fourth edition of Griffiths's Introduction to Electrodynamics.
My only problem with the example, which was something that bothered me in other parts throughout the section, was the very first step. The problem sets us up with two electrodes at constant potential, and asks ... |
I am trying to build a wetland filter for a pond. Basically, you dig a big hole, fill it with rocks (large at bottom, small at the top), and pump water deep under these rocks, so the water slowly trickles upwards.
The major problem with such as system, is you have a pump that pumps the water, and but you need to distri... |
N has 7 protons and 7 neutrons per atom. So the spin is S=1 for one N-atom. Why is this? I know that they do pairs in the shell model. So I only need to look at the spin of a single proton and a single neutron in N. If both spins are parallel it is 1 or -1. But why is 0 not an option for this (antiparallel spin ex. S =... |
If you imagine light source passing through a single slit of variable thickness, as you lower the thickness of the slit the light will diffract more and more until the slit is small enough that no light is passing through.
Is the minimum size of the slit through which light can successfully pass the amplitude of the li... |
Suppose we drop from rest, a body of mass $m$ and breaking stress $\sigma$ on the ground from height $h$ and it collides with the perfectly rigid ground and comes to rest within a short time $t$. The coefficient of restitution is taken to be $0$ for simplicity.
For maximum height, we can equate impulsive force to break... |
In 'Non-abelian Bosonization in Two Dimensions', Witten writes down the commutation relations between currents and fields of the WZW model in equation (33):
\begin{equation}
\bigg[\frac{1}{2\pi}\bigg(\frac{dg}{d\sigma}g^{-1}(x)\bigg)^{ij},g^k_l(y)\bigg]=-i\delta(x-y)(\delta^{jk}g^i_l(y)-\delta^{ik}g^j_l(y)),
\end{equat... |
A few physicists (or computer scientists) take it for granted that the universe is a computation. However, I am not able to understand how the universe CAN be a computation in the first place.
I come from Classical Mechanics background, and I have not formally studied "Theory of Computation", so pardon me for the gaps ... |
In Young's double slit experiment interference patterns are formed. And my question is what is meant by "fringe". Is it only dark band or bright band? I am confused because formula for width of fringe is $\frac{\lambda D}{d}$ which is equivalent to Dark band and Bright Band together. So what's happening?
As you can c... |
I am not a physicist, but rather a middle school science teacher. Please be gentle. The marching soldiers has been a really good analogy for explaining why a change of direction is caused by hitting the boundary of a new medium at a non-normal angle. In a pre-Covid time, you could actually have students do this in the ... |
The time rate of change of the vector $\mathbf{G}$ as seen by
the two observers is then obtained by dividing the terms in Eq.
(4.81) by the differential time element $dt$ under consideration;
$$\bbox[yellow]{
\left(\frac{d\mathbf{G}}{dt}\right)_\text{space}
=\left(\frac{d\textbf{G}}{dt}\right)_\text{body}
+\bold... |
I understand that two uncharged plates places nanometres apart experience a net force due to their interference with the quantized fields around them.
I'm wondering whether or not this force fluctuates randomly as is the case with most quantum effects, even if the average force is constant.
|
If one takes the Liénard–Wiechert Potential, swaps the charge with mass of the point and replaces $\frac{1}{4\pi\epsilon_0}$ with G, one gets a time retarded potential for gravity. Taking the gradient gives an expression for the the acceleration a particle feels at that point due to gravity.
Of course this doesn't give... |
Is there any possibility to explain gravitational time dilation as a result of space being constantly moved by the gravitational attractor towards its centre? (Something similar to 'frame dragging'). So the EM-waves emitted by a body moving towards the attractor move like a person on a reverse escalator, which slows d... |
I'd like to start writing and incorporating my own 3D physics engine in to my game engine, and after doing a little research in to what one might need to have a firm grasp of before doing such a thing it started to seem a little daunting.
I've found that apparently Classical Mechanics (Goldstein and friends) is a great... |
The problem of the particle in the external magnetic field is one of the most famous and oldest problems in quantum mechanics. Hamiltonian of the particle in the constant magnetic field is:
$$
\mathbf{H} = \frac{1}{2 m} (\mathbf{p} - e \mathbf{A})^2
$$
And the solution for a particular choice of gauge $A = (0 \ \ Bx \... |
I was recently solving a physics problem that gave you the electric field $$E(x, y, z, t) = E_{0}cos(k_{y}y + \psi_{y})sin(k_{x}x-{\omega}t)\hat{z}$$ and the question asked for a variety of things including $k_{y}$, the dispersion relation, and the lowest frequency that will propagate. With the boundary conditions E = ... |
We know that if there are two observers S and S', they will observe some events on the space-time and their relation is given as
$$\Delta x = \gamma(\Delta x' + \beta \Delta c t')$$
$$\Delta ct = \gamma(\Delta ct' + \beta \Delta x')$$
Now my problems is about the meanings of the $\Delta x$ and $\Delta x'$. If we have a... |
Im reading about Entanglement Spectrum in very nice webiste here.
It says:
After a system is partitioned into subsystems {A} and {B}, a state of the entire system may now be expressed as a matrix with rows and columns given by the state vectors from the Hilbert space for {A} and the state vectors from the Hilbert space... |
I'm working on a project which uses cylindrical permanent magnets, and I'm trying to determine the expected magnetic field due to these magnets. One problem I run into is that these magnets are usually not completely horizontal above the point at which I want to calculate the expected magnetic field. Assuming the point... |
I came across a problem in the context of degenerate perturbation theory.
$
\newcommand{\ket}[1]{|{#1}\rangle}
\newcommand{\bra}[1]{\langle{#1}|}
\newcommand{\braket}[2]{\langle{#1}|{#2}\rangle}
\newcommand{\acomm}[2]{\left\{#1,#2\right\}}$
Consider a pair of two spin-1/2 systems with orthonormal basis $\{ \ket{\uparr... |
I've just seen these without any explanation of what the variables are or what are do they describe, I just know it should be something about convex lenses and starting fire with them.
$$Q_r=C^n(-\Delta H_r)Ze^{-\frac{E}{RT}}$$
I'm not sure if the triangle represents delta as change or if it's a Laplace operator
$$C_p\... |
I have a watch (Casio G-Shock GW-M5610 ) which can synchronize itself to radio time signals. In my area it uses DCF77 tower, which transmits 77.5 kHz (approximately 3868.3 m wavelength) signal:
The DCF77 station signal carries an amplitude-modulated, pulse-width
coded 1 bit/s data signal. The same data signal is also ... |
When reading Prof. David Tong's notes on FQHE, I got a question regarding the Haldane pseudopotential. We have the unique analytic solution of the lowest Landau level of two particles with a potential which only depends on the distance between the two particles: $V(r_1,r_2)=V(|r_1-r_2|)$ as:
$$\psi_{mM}(z_1,z_2)=(z_1-z... |
What does gravity look like in a compact space, such as a universe with spatial periodic boundary conditions equivalent to a 3-torus, or a ball with opposite points on the surface of the ball identified? In particular, what is the equivalent to the Schwarzschild vacuum solution to the Einstein field equations? I have o... |
This is a simple texbook problem: A television channel is assigned the frequency range from 54 MHz to 60 MHz. A series RLC tuning
circuit in a TV receiver resonates in the middle of this frequency range. The circuit uses a 19 pF capacitor.
(a) What is the value of the inductor?
(b) In order to function properly, the cu... |
For interactions via a Newtonian gravitational potential, the virial theorem states that
$$ 2 \langle T \rangle = -\langle V \rangle $$
i.e. the time-averaged total kinetic energy and total potential energy are proportional, with a constant factor. In (for example) the Wikipedia article on the virial theorem, this is d... |
I am having trouble in applying the conservation of angular momentum in the following problem.
A uniform rod of mass M and length a lies on a smooth horizontal plane. A particle of
mass m moving at a speed v perpendicular to the length of the rod strikes it at a
distance a/4 from the center and stops after the collisi... |
There is this equivalence between representations for the Dirac propagator: $$\frac{i}{\not{p}-m}=\frac{i(\not p+m)}{p^2-m^2}.$$ The only way i could think this to be true is if $\gamma^{\mu}p_{\mu}\gamma^{\nu}p_{\nu}=p^2.$ What property guarantees this?
I know i'm missing something pretty easy here. Please let me know... |
In the special case where a bowling ball has initial translational velocity but no initial angular velocity, the bowling ball will experience a contact force due to Coulomb friction $\mu mg$.
In the special case where the bowling ball has initial translational velocity $v$ and initial angular velocity $\omega$ such tha... |
The Bohr's model of the atom was defined only for hydrogen and hydrogen-like species.
Yet, the Franck-Hertz experiment was performed with Mercury vapour- which, obviously, isn't hydrogen-like. What's more intriguing is that the observations made were in good agreement with Bohr's model.
Take a look here:
http://hyperp... |
I have recently learnt how to make quilling swirls [also called paper filigree] ,one of the methods to curl the paper strips is to quickly run your fingernail on the underside of the strip you want to curl.
This also works for curling decorative ribbons on gift hampers with scissors.[see Method 1 in the wikiHow page].
... |
We know a human cannot run on water, but could a much stronger and faster animal?
This viral video shows a moose running across a body of water:
https://www.youtube.com/watch?v=K5-0d00hV1c
Some say the video is fake. Others think the water must be shallow. We probably won't resolve these issues here.
My question is: c... |
I am trapped inside the usual elevator and experiencing a comfortable gravitational field of about 1 g. Or perhaps it's an acceleration of 1 g. I cannot tell which.
However, I notice when I drop an object from the ceiling it does not quite drop vertically. Its path bends slightly - always by the same amount in the sa... |
I am doing a problem in which I am drawing free-body diagrams for different objects in a system, and two of the objects which are included in my scenario are Earth and a body of water which is resting directly on earth (the tank/container is being ignored).
What is the force(s) that are present in between the Earth and... |
In Griffiths's Introduction to Quantum Mechanics, while studying the time evolution of the expectation value of position, the author wrote:
$$\langle x\rangle=\int_{-\infty}^{+\infty}x|\Psi(x,t)|^2\,dx.$$
So
$$\frac{d\langle x\rangle}{dt}=\int x\frac{\partial}{\partial t}|\Psi(x,t)|^2\,dx.$$
Did he just assume that $x$... |
Assume a planet of mass $m$ and centre of gravity $G$ distorting spacetime according to the laws of general relativity.
All sufficiently close objects with a much smaller mass - let’s say a mole - will fall on it. On the ground the mole will undergo the planet’s gravity $g$. Let us say the mole digs through right to th... |
A windmill has a rotor attached to a 3-blade system, each weighing 5000kg and measuring 34m in length. How much torque does the wind have to provide to make sure that the 3-blade system rotates at 12 rpm constantly? Assume the wind has to do 1000Nm of work overcoming friction in the rotor.
I can see how torque is need... |
Mathematical structure of classical mechanic is described by symplectic geometry which is a smooth manifold with a non-degenrate closed 2-form $\omega$.
I understand the requirement that $\omega$ should be non-degenrate and conservation of energy along flow lines implies $\omega$ to be a 2-form.
are not these condition... |
I am trying to calculate the thermal efficiency for a cycle which includes a process, where ideal gas gives out heat and its volume decreases. Does this mean, that work is done to the gas? So when I calculate the efficiency, is it simply the ratio of work done by the gas and the heat brought to the gas? Or should I cou... |
High school/ Higher Secondary School standard QA
It is obtained from Wikipedia,
A simple form of interference pattern is obtained if two plane waves of the same frequency intersect at an angle. Interference is essentially an energy redistribution process. The energy which is lost at the destructive interference is reg... |
Recently been studying fluid mechanics and I have a query in context with surface energy.
I am aware that energy is decreased when two drops combine, But not aware of where that energy goes.
Does the temperature of the combined drop increase or is it radiated to the surroundings?
Follow-up question, If it is the first ... |
You know how an antenna works? It creates EM fields and oscilates them so that it creates electromagnetic fields...Well does that electromagnetic wave travel in a straight line or spread out circularly? and Why?
|
Snell's law tells us that,
Sine of angle of incident of light by sine of angle of refraction of light, when light travels from one medium to other, is a constant(for that mediums).
It is also related as ratio of speed of light in two mediums. This ratio is also a constant.
But, how they both are equal? How we came up w... |
We can find the direction of vibration of a particle by shifting the wave in the dirction of wave travels. Is this applicable for EM waves as well?
|
If we have an object submerged in water with a density greater than it then it will sink while objects with less density will float. This is found in many scientific articles and videos.. but why?
Particularly speaking, How do we understand this in a molecular picture? If we think of it using a free body diagram it mak... |
Let's say we have a Yang-Mills $SO(3)$ theory coupled to a real scalar field $\phi$. Then the Lagrangian can be written as
$$
{\cal L} = \frac{1}{2}(D_\mu \phi)^T D_\mu \phi + \mu^2 \phi^T \phi - \lambda (\phi^T \phi)^2 - \frac{1}{2}tr\left\{ A_{\mu\nu}A^{\mu\nu} \right\},\qquad D_\mu \phi = (\partial_\mu + iA_\mu^a T^... |
Given the probability density
$$\rho = \frac{i\hbar}{2mc^2}(\psi^*\partial_t\psi - (\partial_t\psi^*)\psi) = |\mathcal{N}|^2|\Xi|^2$$
where $\mathcal{N}$ is a (real) normalization constant and $\Xi$ does not depend on $\vec{x}$.
If we want to normalize it such that we find one particle in a volume $V$, we demand
$$\int... |
I am trying to show the uncertainty relation of $\Delta x\Delta p = \frac{\hbar}{2}$ using a gaussian wave function and its Fourier transform. I have found correctly the uncertainty in position $\Delta x = \frac{\sigma}{\sqrt 2}$ and am trying to find the uncertainty of the wavenumber to get the uncertainty in momentum... |
There are at least two ways to argue about the velocity (or current) in band theory.
The first one is the group-velocity formalism
$$\mathbf v_g = \frac{1}{\hbar} \nabla_{\mathbf k} \epsilon_{\mathbf k}$$
and the second one is the current operator formalism
$$\mathbf J = \frac{\hbar}{2mi} \psi^\dagger \nabla \psi + h.c... |
In most explanations of how antennas work they say that because of kinks in the electric field of an antenna meets at one point and detaches... I looked up reasons for why this happens but all I got was an answer saying that electromagnetic waves travel in the direction of the Poynting vector.
So I have 2 questions:
W... |
Griffiths' Introduction to Electrodynamics, 4th Ed. features the following question:
What current density ($\vec{J}$) would produce the vector potential $\vec{A} = k \hat{\phi}$, where k is a constant, in cylindrical coordinates?
Now, there are two equivalent approaches to the problem:
Using the definition of the magn... |
https://www.youtube.com/watch?v=ubZuSZYVBng&t=329s
In the video above the man put a 200 thousands volt ball near a non-charged one and a very tiny current appear between them. But I think with high electric potential difference between them, the ions should be pushed with higher force since F=q.E and thus more charge p... |
Do Einstein's field equations admit a solution such that spacetime was empty in the past of a hypersurface of constant time say $t =0$, but in the future there exists a non-vanishing energy momentum-tensor $T_{\mu\nu}$?
If so how can we justify that?
|
The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time, and is constant if and only if all processes are reversible.
For an isolated system, for both reversible and irreversible process dQ = 0. So according to the equation of entropy isn't dS always zero for an... |
A policeman measuring motor vehicle noise is exactly 7.5m from the line of traffic on a straight road . The Sound Intensity Level ( SIL) reading shown on his meter is 86 dB. An isolated house faces the road and is exactly 30m from the line of traffic . What will be the SIL reading if he measure outside the house .
and ... |
To the extent, if you make a postulate based on the observation that can not be described with classical mechanics, this is how quantum mechanics was initially put in and then we ask what's its prediction? what's are the result? What's is predicted and then we again do an experiment and then check the theory and formal... |
I've been searching about OCT imaging and understood that it is based on low-coherence light source. The problem is, I don't understand what is a low-coherence light source. Based on what points that we call a light source have low-coherence? My reading source so far hasn't come up with anything about this.
|
Consider a conservative force $\vec{F}=F_1\hat{i}+F_2\hat{j}+F_3\hat{k} $ acting through a displacement $\vec{ds} =dx\hat{i}+dy\hat{j}+dz\hat{k}$. The work done $dw$, will be equal to $F_{1}dx +F_{2}dy +F_{3}dz$. From the work-energy theorem, this is equal to the change in kinetic energy $dK$.
However, since the for... |
Laskar https://arxiv.org/abs/1209.5996 calculated the position of planets up to 5 billion years. The time period is chosen to cover a time scale before the Sun is thought to expand as a red giant.
In his calculations, Laskar found that there is a tenfold increase in an error of the earth position along its orbit over 1... |
To those who are familiar with nuclear physics, I have two questions of understanding:
Why does it happen that nuclei have a spin greater than 1 (e.g. I=8 at 90Nb)?
How can we infer the parity of a nucleus?
My ideas:
1): I have the nuclear shell model in mind. If the levels for protons and neutrons are filled one a... |
I am trying to measure the MTF of a radiology imaging system from a set of CT scans of a phantom. The imaging system is primarily designed for stationary scans so the CT images were low in spatial resolution. I am not particularly familiar with optics and I cannot come to a physical understanding of the results I produ... |
According to Newton's 3rd law, $ F_{A\to B} = -F_{B\to A} $, when you apply a force to an object, it applies the same force (against you?).
When I stretch a strap with my hands, which force exactly is it generating in return?
|
What if the net force on some particle is zero and we choose that particle itself as the reference frame or a frame moving uniformly relative to the particle. Can we call that frame an inertial frame of reference?
|
Which textbook do you suggest for an advanced study of critical phenomena?
|
From what I understand, all statistical theory proceeds by assigning probabilities to microstates based off some ergodic-like assumption, and then looking at the implications of this on properties of macrostates. First of all, is this accurate?
Second of all, if true, are there examples where probabilites are assigned ... |
From a quantum information theoretical point of view, how is deterministic state transfer related to entanglement generation between two qubits? Or, more specifically, how can you exploit the former to achieve the latter? Would such entaglements protocols be suitable for superconducting xmon qubits? If yes, how?
|
If you asked me what physical result would be naturally referred to as "the no-deleting theorem", then I would probably guess something like this:
Given a designated "blank" state $|0\rangle$ in a system's Hilbert space and two fixed states $|a\rangle$ and $|a'\rangle$ in an ancilla Hilbert
space, there is no single l... |
Partition function on torus can be defined using a generalized Witten like index as given below:
$$F_1=\int_\mathbb{T}\frac{d^2\tau}{\tau_2} Tr(-1)^F F_LF_R \;q^{L_0} \bar{q}^{\bar{L_0}},$$
where $\mathbb{T}$ is the fundamental region for $\tau$ defined in upper half plane.
My question is pretty simple and that is to e... |
Does anyone know how I can get a hydrodynamic model of the compression of a syringe by means of the force of a motor ($ F_ {M} $). Where $ F_ {atm} $ is the force due to atmospheric pressure, $ F_ {r} $ is the frictional force obtained by the friction between the plunger and the walls of the syringe and $ F_ {l} $ is t... |
I have read that, in the nuclear shell model, nucleons are distributed filling energy levels following the Pauli exclusion principle. These energy levels can be designed with the $nl_j$ notation: $1s_{1/2},1p_{3/2},1p_{1/2}, 1d_{5/2},...$
I have two questions in relation to this matter:
Do protons and neutrons fill th... |
I'm studying Schwinger's action principle in Classical Field Theory, but I have some doubts about the correct variation of the Lagrangian density. Let's consider an infinitesimal transformation of coordinate and fields
$$
x^\mu\rightarrow x'^\mu=x^\mu+\delta x^\mu \\
\phi_s(x)\rightarrow\phi'_s(x')=\phi_s(x)+\delta\phi... |
I'm supposed to use the Lagrangian approach in the solution. I've just recently started classical mechanics course and it's still somewhat confusing to me.
The problem I am working on is as follows: "2 masses $m_1$ and $m_2$ are connected with a line across 3 pulleys of which the middle one has mass $M$ and can move f... |
Ordinarily in Newtonian physics, velocity is defined as $${\vec v}=\frac{d{\vec x}(t)}{dt}$$ where we use the coordinates of an observer and the universal time $t$.
When we dive into special relativity, we define the spatial components of the four-velocity as $$v^i=\frac{dx^i(\tau)}{d\tau}$$ instead of $$v^i=\frac{dx^i... |
Sorry for eventual factual errors, I am just hobbyist.
A spaceship flies with nearly speed of light away from earth and back.
Time on board were going slower than on earth during flight, so back on earth the pilot is younger than his twin on earth, also the pilots clock show that less time got by for him than for his f... |
When transforming a field in classical field theory the transformation of the four-gradient of this field follows automatically. At least this is what i have learned in my lectures.
This circumstance kind of contradicts my understanding of the Lagrange formalism in classical mechanics. In classical mechanics the genera... |
I was reading a paper about the ANITA balloon-borne experiment. In Table 1 in the paper, the experiment times for 'flaring blazers searches' are denoted as 'year-month-day 15:43:38Z + weeks'. In the caption of the table the authors explain that the number "15:43:38Z" is an offset and is related to the Fermi-LAT mission... |
I am creating a simulation of a magnet moving relative to a copper coil generating emf in it. So far I am working with emf generated, current, resistance, resistivity, turns, coil length, and the cross-sectional area of the coil. The next step is to add the increase in temperature in the coil as a result of flow of ele... |
I am just wondering the 4 Maxwell equations (i.e Fadaray Law, Maxwell-Ampere) are Lagrangian or Eulerian description? Does it really matter?
|
Consider a block of mass $m$ moving with initial velocity $v_o$ attached to a spring with spring constant $k$, on a terrain which has a coefficient of kinetic friction $\eta$ and coefficient of static friction $\epsilon$. Find the time taken for oscillations to die off.
If we write the force equation of block when i... |
As I begin to read literature on Anderson localization by disorder, authors are distinguishing between cases that are unfamiliar to me, namely weak localization, strong localization, and localization without a metal-insulator transition.
Can anyone suggest a reference to help me understand the meanings of these terms, ... |
When something floats, it is due to the buoyant force from the liquid onto the object, but what force does the object exert in response down on the liquid? I feel as if the object would have to exert a downward force on the liquid due to Newton's Third Law, but I haven't been able to figure out what it would be.
|
I am trying to solve a problem in which light is normally incident on a material of refractive index n which is coated with an anti-reflective coating of refractive index $n^{\frac 1 2}$ and thickness equal to $\frac 1 4 \lambda$ ($\lambda$ being the wavelength). I need to show that under these conditions there is no r... |
So, I'm going through my first quantum mechanics class in university and I feel like there is not a strong distinction made between a purely mathematical system and purely physical system, which are not exactly the same.
To me, for all the classes I've took so far, it seems like we model physical phenomenon by creating... |
I was going through this question, now I wonder what are necessary criteria for describing a system as quantum system.
Is it so that we have evidence of nuclear shell structure that imply that nucleus is a quantum system? As shell numbers turns out to discrete which leads that nucleon can have only certain fixed energy... |
My goal is to understand whether or not there would be a source term $\rho$ in the Helmholtz (or Poisson) equation for the scalar electric potential, for the region inside an object with finite conductivity, hooked up to an alternating voltage source.
Consider an object with a finite conductivity $\sigma$, which is con... |
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