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Even though the pressure increases when the area of contact decreases why doesn't friction increase with decrease in area?
|
Can anyone explain why does the depletion region not vanish completely, but only shrinks, on forward bias?
|
I have three questions about 3 successive measurements of the spin of an electron.
In the first measurement the spin is always measured to be +1/2 on the z-axis. Measurement 2 and measurement 3 are done several seconds after the first measurement. I assume that there is no interaction with other particles during this ... |
Consider the example case:$$|\phi\rangle=\frac{1}{\sqrt{2}}(|01\rangle-i|10\rangle)$$ From this we can easily calculate the density matrix:$$\rho=\frac{1}{2}\begin{bmatrix}0&0&0&0\\0&1&i&0\\0&-i&1&0\\0&0&0&0\end{bmatrix}$$Now trying to calculate the von Neumann entropy I could probably say that "it is a pure state, erg... |
Abstract
Some time ago, someone gave me the next solution:
$$U=-\int \vec{m}\small{(x)}\times \vec{B}(x)dV$$
$$\vec{F}=-\nabla U$$
In other stack site I’ve asked, how to solve it numerically, and one user pointed that formulas are wrong, because $U$ is a number, not a field, and, hence, gradient operation can’t be appl... |
I would like to understand,from a macroscopic approach, the evolution of thermodynamical properties whithin certain systems :
1) There is water inside an isulated vessel at 100°C, 1 Atm. I can´t assure whether it is steam, liquid, or a mixture of both (but ratio unknown). Since it is in Vapor- Liquid equilibrium, eithe... |
I am currently studying Classical Mechanics, 5th edition, by Kibble and Berkshire. Chapter 1.2 Newton's Laws says the following:
If we denote the force on the ith body due to the jth body by $\mathbf{F}_{ij}$, then
$$\mathbf{F}_i = \mathbf{F}_{i1} + \mathbf{F}_{i2} + \dots + \mathbf{F}_{iN} = \sum_{j = 1}^N \mathbf{F}... |
Assuming some random object (spherical cow/brick) reaches a speed v in free fall:
if you pick this same object and you accelerate it horizontally up to the same speed v in the same type of atmosphere, pointing the same side of it in the direction of movement,
would this object be able to maintain flight?
|
I viewed a similar question but that didn't solve my query.In the shown problem, while solving the equations my teacher just assumes that the static friction will have its maximum value and solves the question,(NOTE: there is no friction on the inclined surface, it is only on the flat one)
What I can't understand is w... |
The Hamiltonian of the Heisenberg XXZ chain (without external field) has the form
$$
H = -J \sum_{n=1}^{N}\left(S_n^xS_{n+1}^x+ S_n^yS_{n+1}^y + \Delta S_n^zS_{n+1}^z\right).
$$
It is known that this model has three phases, for instance, from this book,
1. Ferromagnetic for $ \Delta > 1 $
2. Paramagnetic for $ -1 \... |
I know that in field theory Euler Lagrange equations are $p_i-d_\mu p^\mu_i=0$.
(Classical notations, $p_i=\frac{\partial L}{\partial y^i}, p_i^\mu=\frac{\partial L}{\partial y^i_\mu}$).
Being a differential equation, I can expand it to first (or higher) order, but how can we do this?
I was wondering if it is right to ... |
When a ferromagnetic material is magnetized (by application of an external magnetic field), the domains are aligned in the direction of the field, and the ferromagnetic material itself acts as magnet whose north pole is near the south pole(of the field) and vice versa.
If this is so, don't the two fields (the external... |
I understand that a quarter wave plate converts linearly polarised light (single axis) to circularly polarised light (two axes) with one wave delayed by quarter of a wave length. I understand that this result can be achieved by linear light being polarised through a lens angled at 45 degrees:
Source: https://www.edmu... |
why is it that when a ball spinning on a rope has a centripetal force larger than the tension of the rope (due to exceeding the maximum velocity), the rope breaks and the ball goes off in a tangent? is it not the centripetal force what keeps it going in a circle and so it will continue going in a circle since there is ... |
In a recent examination i encountered a question in which a current carrying coil was rotated clockwise about its own axis in a uniform magnetic field directed along the axis and out of the plane of the paper (refer the image provided below) and they asked the variation in tension in the wire.
I know that if the loop ... |
Consider some known physical fact, e.g. $\nabla \cdot \mathbf B = 0$ for the magnetic induction $\mathbf B$. Now, is it possible that a mathematical theorem exists, which yields a wrong prediction?
E.g. a hypothetical - correctly proven - theorem that goes: "If $\nabla\cdot\mathbf B=0$ then some new planet should be b... |
How is a generalized coherent state $|m,\alpha\rangle$ different from a photon added coherent state $|\alpha,m\rangle$ ? And are they orthogonal?
|
Suppose, in inertial reference frame $F_1$, observers A and B are at rest, each having torch, and are separated by some distance and we have put machine M at middle of A and B.
Machine M has light bulbs on both sides ,right and left, so that if it catches light from A which is at left ,then machine M glows left light b... |
Ok let us take an example of a book placed on a table and in first case let us say that it is on an aeroplane at rest. Since the book is at rest this means that the weight is balanced by the normal of the table.
But if the same ( book + table ) system is kept on a flying aeroplane (in horizontal direction with constant... |
I have learnt that by doing a saddle point approximation in the path integral formulation of quantum mechanics, the classical action (extremal action where $\delta S=0$) is the one that contributes the most, hence seeing how classical physics arises from quantum physics.
The question is: is there any example in quantum... |
I had asked whether the frictional force depends on the surface area in contact but the expets says no...
So why does the rolling friction less than that of sliding friction...?
Sliding friction is the friction which an object experience when it is slid over a surface but the rolling friction is experienced when an obj... |
If you solve for $dt$ from $a = \frac{dv}{dt}$ , is it the time taken to to achieved that instantaneous acceleration?
$a$ : acceleration
$v$ : velocity
$t$ : time
|
I consider a Hamiltonian describing the interaction between a system and a bath, namely $H = H_0^S + H_0^B + H_I$. In the interaction picture, the Schroedinger equation for the unitary operator $U_I(t,t_0) = U_0(t,t_0) U(t,t_0)$ is
\begin{equation}
i \partial_t {U}_I(t,t') = \mathcal{H}^{int}_I(t) {U}_I(t,t').
\end{equ... |
If I set $N=1$ and $N^a=0$ in the Einstein-Hilbert action $$S[N,N^a,q_{ab}]=\int\sqrt{\mathrm{det}(g)}\,R\,\mathrm d^4x \,\text{,}$$ expressed in terms of ADM variables, then $N$ and $N^a$ are no longer configuration variables for this gauge fixed system anymore. Consequently, I don't need to compute their conjuage mom... |
Consider pure QED with massless electrons. Due to the axial anomaly the axial current is not conserved:
$$
\tag 1 \partial_{\mu}J^{\mu}_{5} \sim F_{\mu\nu}\tilde{F}^{\mu\nu}
$$
On the other hand, it seems that this non-conservation has nothing to do with the particle physics processes, as there is no axial field couple... |
I've always treated propagator in the momentum representation so when it diverges, we are on-shell. But what is the interpretation of light-cone divergences in position space? If it is something we have to renormalize, how can I do it? More precisely, if I have to renormalize light-cone divergences of the following Fey... |
It seems to me (correct me if I am wrong) that all theories in the Standard Model are exactly renormalizable, as opposed to non-renormalizable or super-renormalizable. In a sense, we could say that these theories live at a critical point, that is on the boundary between non-renormalizable and super-renormalizable theor... |
I have a conceptual doubt in ideal fluid flow. I have expressed my doubt with the help of the following example.
Suppose an ideal fluid flows along a flat tube of constant cross section, in a horizontal plane and bent as shown in the figure below. The flow is ideal and steady.
The question is - All the fluid elements... |
I had a question as follows:
A tennis ball is a hollow sphere with a thin wall. It is set rolling without slipping at 4.03 m/s on a horizontal section of a track as shown in Figure P10.64. It rolls around the inside of a vertical circular loop of radius r 45.0 cm. As the ball nears the bottom of the loop, the shape ... |
Schwarzschild metric at the event horizon shows that, a small distance as perceived by a distant observer is in fact an infinite distance for a falling observer. Yet the falling observer crosses the event horizon and untimately reaches the centre singularity in a finite time. Doesn’t that create a paradox?
How can som... |
I am wondering
(A) about the influence of individual spins on the behavior of a macroscopic object
(B) and about the influence of rotating the macroscopic object on the internal spins
To approach this in a systematic way, maybe consider the following points:
Concerning (A)
Confirm that two opposite spins or a rando... |
Gravitational field depends on mass ($g = \frac{GM}{r^2}$) and every year many outside cosmic objects like asteroids or tiny object are hitting earth. So I think may be in a very microscopic amount the mass of Earth is increasing. But does it increase the Gravitational Pull or Gravity on Earth?
And also, does it result... |
An infinite cylinder of radius R has a uniforme current distribution through its surface $\vec \kappa (t)=\kappa(t)\vec \phi$. Find a) the magnetic field generated by the distribuition, b) the induced electric field, and c) the Poyinting vector for this configuration.
So far, I have used Ampere's Law to determine the... |
I am currently studying Classical Mechanics, 5th edition, by Kibble and Berkshire. Chapter 1.2 Newton's Laws says the following:
However, this does not completely remove the difficulty, for there is still an apparent contradiction between this classical electromagnetic theory and the principle of relativity discussed ... |
I would like to create program for calculation exoplanet properties, but I only found transit dataset from Kepler on NASA website. From light curve I can calculate:
planet radius $r$ from $\frac{r_{planet}^2}{R_{star}^2} = brightness\ drop$,
semi-major axis $a$ from $p^2 = a^3\frac{4\pi^2}{G(m_{planet} + M_{star})}$,
... |
A container has 2 immiscible liquid of different densities. Suppose water on botton and kerosene oil on top. A body floats at the boundary of both such that it is partly in water and partly in the oil.
Now just consider the force in the upper liquid kerosene. The forces on the side of the body are equal and opposite s... |
I searched in the forum and found the maximum distance is $r=1.75\times 10^{-15}
m$. Ok, imagine an electron hits a plate with charge of 1 proton, the result of Coulomb's law is $230$ Newtons. Obviously it has an error, is the distance $r=1.75\times10^{-15} m$ wrong? I think the distance should be much larger to vali... |
One mole of a certain ideal gas is contained under a weightless piston of a vertical cylinder at a temperature $T$. The face of the piston opens into the atmosphere. What is the heat supplied in the process to expand the gas from volume $V_1$ to $V_2$ isothermally ? Friction of the piston against the cylindrical wall ... |
How does a hologram create parallax, compared to a photograph? If a hologram's purpose is to reproduce the light field, what part of that field creates parallax (angle, magnitude or position)?
|
I am having trouble understanding what off diagonal elememts of a density matrix represent. I know that it tells you the coherence but i dont undetstand why. Like in case of diagonal elements it tells you the probability of finding the system in some state because the diagonal terms are the product of the complex numbe... |
Reference:https://web.mit.edu/16.unified/www/SPRING/propulsion/notes/node16.html
The throttling process is a constant enthalpy process, in which the pressure decreases. So,
$$h_1 = h_2$$
$$u_1 + p_1v_1 = u_2 + p_2v_2$$
If the pressure is decreasing and if we consider the Joule-Thomson coefficient to be such that the te... |
In the potentiometer, if the emf of primary cell and secondary cell are not equal, then the wire connected to primary cell and secondary cell will have different potential. Suppose the emf of the secondary cell is lower, then the positive charge in the wire connected to primary cell should flow towards the secondary ce... |
A train consists of an engine and $n$ trucks. It is travelling along a straight horizontal section of track. The mass of the engine and of each truck is $M$. The resistance to motion of the engine and of each truck is $R$, which is constant. The maximum power at which the engine can work is $P$.
The train starts from ... |
In QFT the propagator is divergent for the on-shell momentum of the particles. When e.g. calculating the amplitude for a box loop, the propagator diverges for on-shell particles running in the box-loop.
Is there a physical interpretation for this divergent behavior?
|
From Wikipedia:
In the case of systems composed of m > 2 subsystems, the classification of quantum-entangled states is richer than in the bipartite case. Indeed, in multipartite entanglement apart from fully separable states and fully entangled states, there also exists the notion of partially separable states.
Does ... |
I want to know how we find or construct the matrix representations for Grassmann numbers.
For example, we can see from https://en.wikipedia.org/wiki/Grassmann_number:
Grassmann numbers can always be represented by matrices. Consider, for example, the Grassmann algebra generated by two Grassmann numbers 1 and 2. These G... |
Current is the flow of charges (many say electrons).
Do these charges flow just between the terminals of the source/battery (terminal to terminal) ?
Or
Do these charges flow through/inside the source/battery as well?
What I know is that the positive terminal is the lack of electrons as compared to the negative terminal... |
Are Greenberger-Horne-Zeilinger (GHZ) states defined by:
$$ |GHZ_{d}^{M}\rangle = \dfrac{1}{\sqrt{d}} \sum_{i=0}^{d-1} |i^{ (1)}\rangle \otimes \cdot \cdot \cdot \otimes |{i}^{ (M) }\rangle $$
by default isotropic, or is that only true for the case $d=2$?
|
As shown in the following, a rigid body experiences an external force $\overrightarrow{F}$ away from its center of mass C:
The rigid body is assumed to be free in space, experiencing no other force.
According to the theorem for the center of mass, the center of mass should have an moment acceleration $\frac{\overrigh... |
I understand that weak interactions are the exchange of W and Z bosons between leptons and quarks (as explained in this other question: Weak Interaction), but when I read Light Sterile Neutrinos: A White Paper it stated that:
A sterile neutrino is a neutral lepton with no ordinary weak interaction except those induced ... |
Using Kepler's laws of gravitation we can determine the time period of a planet revolving around the sun.
However, this excludes the gravitational effect due to satelite(s) orbiting around the planet.
How much difference would this create in the time period of a planet?
For a simple model of a planet of mass $M$, Radi... |
In high energy accelerator collisions, why does the De Broglie wavelength of the incident particle affect the type of interaction it has with the target nucleus?
E.g. In 280 MeV proton, "direct reactions", the De Broglie wavelength is comparable to nucleon-nucleon distances so proton interacts with a single nucleon not... |
It's common for students to be introduced to tensors as "things that transform like tensors" - that is, their components must transform in a certain way when we change coordinates. However, we can do better by defining a tensor as a multilinear map from $ V\times...\times V\times V^\ast\times ...\times V^\ast\to \mathb... |
I've been wondering if it is possible to control atoms'/molecules' motion in a limited range of movement? (Take different orbits for example)
Let's think mathematically, is it possible to force a/an atom/molecule to only move between the desired A and B point(Or to force an atom to move to another orbital)?
|
I was reading about lens from a book . There I couldn't make about the principal axis for billetsplit cutting of lens . As it can be seen from the above image that two lines L1 and L2 are drawn and claimed to be the principal axis of the cutted lens . But how are the lines drawn ? Please help me in understanding it cle... |
I tried to resolve $G$ from natural units (like Planck), and found that
$$ G = (K \times c / r_0)^3 $$
where
$ G = 6.67430 \times 10^{-11} $ is gravitational constant,
$ K = 1.66053906660 \times 10^{-27} $ is unified atomic mass units (Daltons) per kilogramm,
$c$ is speed of light in vacuum,
and $ r_0 \approx 1.2... |
I am trying to solve the Liouville eqaution of the classic harmonic oscillator with fluctuating energy and arbitrary initial condition $\rho_0$. I want to approach the problem using the method of characteristics. So, given hamiltonian:
$$H = \frac{1}{2}(p^2 + q^2)$$
In addition the expectation value of the Hamiltonian ... |
Considering a circular motion with no angular acceleration. How can you find the same magnitude for the velocity vector at different time using the formula $v_{t} = v_0 + a.t$ with vectors?
The acceleration vector $\vec{a} = \vec{a_c} + \vec{a_t}$ where $\vec{a_c}$ is the centripetal acceleration $a_c$ = $\dfrac{-v^2}{... |
Consider a gauge theory with $SU(2)_{left}*SU(2)_{additional}$ symmetry.
By $additional$, I mean adding a new symmetry between an electron and a quark(like up quark and electron forming a doublet).
And $SU(2)_{left}$ is part of the total SM symmetries.
-Can such theory contain confinement?
-If yes what are the bound s... |
I would like to understand what's happening to a signal emitted from a moving source and arriving to a moving receptor. But, when I am looking on internet about Doppler effect, I can only find equations linking received frequency to emitted frequency. But what I want to do here is to simulate the Doppler effect on a ra... |
I'm asked to show that contracting indices of this Ricci Tensor:
\begin{align}
\newcommand{\ogamma}{\overline{\gamma}}
\newcommand{\OGamma}{\overline{\Gamma}}
\newcommand{\OD}{\overline{D}}
R_{ij} = & \; \overline{R}_{ij} -2 \left( \OD_i \OD_j \ln \psi + \ogamma_{ij} \OD^2 \ln \psi \right) \notag \\
& + 4 \left(
\l... |
We still don't know many thing going inside living cells so I'm wondering whether it's possible to create a math/computer model operating on basic known particles (or higher level composite particles to simplify the process), atom/formula bonds in order to simulate simplest life forming (given all the conditions for ... |
Four material points, all of mass m, are aligned along a straight line and connected two by two by two equal springs, of elastic constant k and rest length $l_\epsilon$. The points are subject only to the elastic force of the springs. Initially points 1 and 2 move spaced of a distance $l_\epsilon$ and both with velocit... |
I have a conceptual question regarding the relation between hopping energy and Fermi Energy.
In order for my question to make sense contextual background is needed:
So the hopping integral or hopping energy definition is given by $$t_{\alpha}\equiv-\int{u_L}^{*}\,V_L\,u_R \,dx=-\int{u_R}^{*}\,V_R\,u_L \,dx$$
The hopp... |
I have a series of exercises regarding C, P and T symmetry but I am not really sure how to start with the problems. If anyone could help me with one of the problems, or show me a few example problems with full solutions, I would be very grateful. Then I can hopefully solve the remaining problems myself... As an example... |
I've seen a toy at my local pharmacy called The Black Hole that lets you insert a quarter into a vertical slot. The quarter starts rolling around a curved funnel's circumference and slowly winds its way to the funnel's center. Unlike most funnel wheels, this funnel's slope is curved from almost horizontal to nearly ve... |
I am considering the photon as a particle.
The incident energy may be equal to the reflected energy, but I would like to know if there is any theory or way of demonstrating that the incident photon in a mirror may be exactly the same as it reflects.
|
After the renormalization procedure, fields will gain an anomalous dimension, $\gamma$, which means that their scaling dimension will be different from what we would guess from the dimensional analysis. My question is whether this means that the action will no longer be dimensionless and if so what are the consequences... |
So according to google:
a photon is a particle that transmits light.
Ok, but light is considered a wave, not a stream of particles(I'm pretty sure that this is what Young's double slit experiment proved?)
So what is it exactly? I assume something like wave-particle duality comes into play here, but i don't know muc... |
We know that the post measurement states after a projective measurement has the form
$$\frac{\hat{\Pi}|\Psi(t)\rangle}{\sqrt{\langle\psi(t)|\hat{\Pi}|\psi(t)\rangle}} \qquad (1) $$
When a position measurement is made, with finite accuracy $\delta$, we can define $\hat{\Pi}_{x_i}= \int_{x_i }^{x_i+\delta}{|x\rangle\lan... |
I have been thinking recently about how one could introduce and motivate elementary mechanics starting from the hamiltonian (or lagrangian, but that is not mostly what I'm thinking about) point of view, without going through Newton's laws. I don't claim this makes sense or is a good idea — consider it an idle intellect... |
Starting from the transformation law for the classical Dirac field
under Lorentz transformations $x \rightarrow ax$ and $\psi(x) \rightarrow \psi\prime(x\prime) = S(a)\psi(x) $ I will derive the generators of these transformations. Now I am a bit confused since I read following.
$\psi\prime(x\prime)$ and $\psi(x)$ shou... |
Simply that: what is a radio echo? And when it was first discovered?
By searching on Google I get results like Amazon Echo and Echo (radio station)
|
Possibility of Using a Refrigerator to Cool the Earth
I understand that the Earth as a whole cannot be cooled directly by radiating energy away for theoretical reasons. Waste heat has low entropy; effectively raising its entropy to radiate it must cost more than it gains.
I thought about building an impossibly-high tow... |
Why does a plane's fan push air backward instead of forward?
And how does fan push air in any direction? shouldn't air molecules be pushed in the same plane as that of fans blade instead of going in and out of the plane?
How do we determine which direction the air will flow?
|
I am looking at some exercises in an online course in QFT and there is a question about the $U(1)$ gauge invariance of this operator:
$$i\bar{\psi}\sigma^{\mu\nu}\gamma_5(\partial_{\mu}A_{\nu})\psi$$
Initially I thought this operator is not invariant since the $A_{\nu}$ is not gauge invariant itself under $U(1)$ inst... |
Photon addition and subtraction are mathematically given by the creation and annihilation operators.
$\hat{a}^{\dagger}|n\rangle=\sqrt{n+1}|n+1\rangle$
$\hat{a}|n\rangle=\sqrt{n}|n-1\rangle$
The problem is I am unable to visualize where the prefactor comes from physically, when I think of adding (or subtracting) a phot... |
I was reading the paper 'A linear response approach to the calculation of the effective interaction parameters in the LDA+U method' by Cococcioni - (Paper here) .
Quoting from the first paragraph on page 9, 'The screening in metallic cerium is extremely localized..'. Even though this section deals with the calculation ... |
Suppose I have a box divided in a left and a right side and two spinless identical particles moving at random in the box. I measure their position and I am interested in how many particles are on the left and on the right side of the box. According to classical statistical mechanics I should have a probability of $ \fr... |
I have 2 vectors: $$|a\rangle=\begin{pmatrix} 2+i & 2+2i\end{pmatrix}$$ and $$ |b\rangle=\begin{pmatrix} 1+i & 1+2i\end{pmatrix}$$
So basically I need to show that $$\langle a| b\rangle=\langle b| a\rangle^*$$
Attempt of solution:
So when I multiply matrices I get for left side: $$\langle a| b\rangle=\begin{pmatrix} ... |
How can I solve poisson equation with two point charge sources in periodic 1D domain analytically.
$$\dfrac{d^2\phi}{dx^2}=-\dfrac{q}{\epsilon_0}\left(\delta(x-x')-\delta(x+x')\right)\,,$$
where $x\in[-L/2,L/2]$ and $\phi(x)=\phi(x+L)$?
The solution is
$$
\phi=
\begin{cases}
& \dfrac{q}{\epsilon_0 L}(L-2x')x \q... |
I am currently reading up on Dirac's 'The Principles of Quantum Mechanics'.
It is stated there, that for the motion of a free particle with Hamiltonian \begin{equation}H=c(\boldsymbol{\alpha},\boldsymbol{p}+\rho_3 mc^2)\end{equation}
we see at once that the momentum commutes with $H$ and is thus a constant of the moti... |
I am following Schwarz Quantum Field Theory textbook. In particular, I am looking at triangle diagrams with massless fermions. On pg. 623 - 624 Schwarz attempts to calculate $q_\mu^1 M_{5}^{\alpha\mu\nu}$ which should be zero by the Ward Identity of QED. This gives (Eq. 30.29),
\begin{multline}
q_\mu^1 M_{5}^{\alpha\mu... |
With two slits experiment shooting electrons when we place a detector on one of the slits the electrons act as particles.
What will happen if we use three splits and one detector? Will we have an interference pattern? If we do how will it look like?
Also in general if we have $n$ slits and $m; m < n - 1$ detectors how ... |
I would like to learn more about fusion in stars. The question I have is whether there exists a graph showing exactly which elements take part in the reactions.
Here, I managed to find some data about the initial stages of stellar nucleosynthesis, but I'm intrested in knowing what happens later, i.e. what processes are... |
I've heard of zero G flights, but why exactly do we feel weightless when we are in them?
|
In the double slit experiment, when we place a detector on one of the slits, the electrons will start to act like particles. When we unplug the detector they return to acting like waves.
What if our detector was turning on and off with a high frequency in a way that we could not tell for all the electrons if during the... |
As you can see from the image we have inverted pendulum stick fixed to ground by the point "K".Rotation of the stick around is only movement.System has no gravity and friction.Only "F" force is applied to the point "P".The system is exposed this force for "t" amount of time.I want to calculate the change of "ϑ" in ar... |
I was trying to study the linear stark effect and an example of the splitting of $2S\pm2P_z$ orbitals, described here. Can someone suggest to me a reference for the similar material discussed but in some reliable place like some reputed text book or published papers?
|
In Quantum Mechanics (QM), the Planck's constant has the S.I. units of
(energy) x (time). So, how should one interpret that?!
How should I understand the physical meaning of the following relations?
$\frac E \nu = h$
as the "energy content" divided by the "fastness'' of oscillation equals h.
or in terms of the de Br... |
I am trying to compare the wave function obtained by exact method and by approximated method.
The potential is
\begin{equation} V(x)=\frac{1}{2}m\omega^2+Ax\end{equation}
I found a solution but I am wondering what is the series development I have to do to go from function one to two.
|
Physicists at MIT have created the first perfect mirror. If this is true, could enough mirrors be directed at a space ship like Archimedes "Burning Mirror" would at a boat from automated solar farm in orbit work to power spacecraft: How far can usable light be projected from multiple points in orbit to intersect at a s... |
My textbook gives the following derivation of the angular momentum of gyroscopic precession:
The magnitude of the torque is $$\tau = r M g\sin\theta.$$
Thus $$dL = r M g\sin\theta\, dt.$$
The angle the top precesses through in time $dt$ is $$d\phi=\frac{dL}{L\sin\theta}
=\frac{rMg\sin\theta}{L\sin\theta}dt=\frac{rMg}{... |
I was watching a video about "delayed choice quantum eraser experiment", it shows how our knowledge about the system can change past events if they have not been measured yet.
I would like to ask about the thought experiment at 10:26
What if the astronomer chooses to use a screen-type of light projector that accompanie... |
I had a simple question - how many different values can a photon present for spin angular momentum, given that it's spin is 1?
And although I immediately thought "3, since j = 2s + 1" (j being the quantum number for anuglar momentum) - I saw the question had a hint:
"remember that photons have zero mass."
So I googled... |
I went ahead and use python magpylib to simulate a ring magnet joystick, and then graph flux over distance of the ring magnet. Here's the code:
from magpylib.source.magnet import Cylinder
import matplotlib.pyplot as plt
import numpy as np
import magpylib as magpy
# system parameters
outerDiameter, innerDiameter, heig... |
The value of resistance is 3Ω and inductor impedance is j4Ω.
As far as I have learned the wattmeter measures instantaneous power but shows reading for average power. As I solved for the given values the power comes out 12W in both cases even though they are connected at different points in the circuit and I want to kno... |
$\hskip2in$
Starting from a Lagrangian of a disc rolling down on a inclined plane without slipping, given by:
$$
\mathcal{L}=\frac{M}{2}\dot{x}^2+\frac{MR^2}{4}\dot{\theta}^2+Mg(x-L)\sin(\alpha) \tag{1}
$$
where $M$ is the disc mass and $\alpha$ is the angle of the inclined plane. Its Hamiltonian in terms of $x$ coord... |
It takes 8 minutes for sun light to reach the earth . In this case when we see the sun and feel the heat , that energy and heat was generated 8 minutes ago . Now imagine a spaceship is in the same distance from both the sun and the earth and so this light and inf that come from both are in the same time ,
Although the ... |
I don't get it when a question asks power delivered by a battery after t seconds, are they talking about the total energy delivered by the battery in time t seconds divided by the time, or are they asking about the instantaneous power deliver at time t, and if whichever is true how do we calculate it
|
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