instruction stringlengths 31 24.3k |
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I'm doing research for a university project and looking for commercial references for Mu metal, I found out that in my country at P2B (particular to business) level, sheets are significantly easier to acquire than solid rods, so getting a valid invoice for tax purposes is easier if my company purchases a sheet spool.
T... |
I am reading about lock-in amplifiers and came across this example circuit of a mixer:
You have one sinusoidal input signal $e_1$ with a phase $\phi_1$ and the local oscillator has a square-wave signal $e_2$ with a phase $\phi_2$. On the positive half-cycles of the square wave the signals go through the upper transist... |
The question could be understood as if we have two fuse wires one of current rating 1 A and one of current rating 8A then what should be the ratio of their radius?
I tried the following:
We know, $Q = mc \Delta t$
but by Joule's law of heating, we also know that $H = I^2 R t$
Assuming that no heat is lost in the surro... |
I have always taken the definition of temperature to be the kinetic energy Statistical mechanics definition of temperature as the average kinetic energy.
However I have been reading a paper where the dynamics is an atom chain in contact with heat reservoirs at the boundary. In this case the system has a non-equilibrium... |
In case of rolling the rotational velocity of the disc $wr$ will have magnitude equal to $v$. But now the top part of the disc has net velocity $2v $. Does that mean the top part of the disc moves by distance 2v evry second while othe parts of disc move less than that?
And while writing it's total kinetic energy (of a... |
I am currently taking an introductory course on solid state physics. One of the problems I came by while studying asks the following:
Suppose we have a 1 dimensional solid of length L, with N primitive cells and one electron per primitive cell, and a separation between cells of $a$. Suppose also that there is only one ... |
So two figures are given in my book,
One is Deflection of radioactive radiations in magnetic field
and the other is deflection of radiations in an electric field
So the question is why does beta particles deflect more than alpha particles?
And why does this deflection increases in electric field ?
|
The single photon / single electron double slit experiment shows particles appearing as dots on the screen. This is explained as being due to the collapse of their wavefunctions.
However, if they were point particles, we would not be able to see them at all. Instead, they have a radius upto which they appear as bright.... |
In an interesting paper by Scott Aaronson, he demonstrate the learnability of quantum states in a framework of pac-learning in machine learning. Here what he wrote:
But I am wondering what is the role of $E$ and how it is different from any member of the set $\mathcal{E} = \{E_j\}_{j=1}^{m}$, because in the first ineq... |
In special relativity, an object (a box, perhaps) travelling at 0.5c relative to us, if it thinks it's 1lightsecond long in its own reference frame, will look 0.866 lightseconds long to us.
My question can be phrased in a few ways:
If that box stops in front of us - it decelerates from 0.5c in our ref frame to 0 in our... |
I am reading this paper by Milgrom(1983) that suggests a modification to Newton's Second Law in order to do away with the requirement of dark matter on astrophysical scales. My question is regarding a paragraph in Section 3 of the paper that says:
Consider now the question of how an external acceleration affects the i... |
How can you estimate Saturn's mass using data from Cassini's final moments in September 2017 (apoapsis on September 12 at 1:27 a.m. EDT Saturn time at a distance of about $1.3*10^6$ km from Saturn, last signal was recorded at 6:32 am EDT September 15?
My ideas: Using Kepler's Laws and using the following information I ... |
(Note, I'm not a physics expert.)
Imagine an elongated (oblong) device with some liquid inside. This device can change its center of mass by changing the distribution of the liquid. Let's say, the liquid can be in one of two polar opposite places of the device.
Now imagine this device being weightless in a free fall a... |
I am now reading about the tetrad formalism in GR and I am starting (how not) with the Wikipedia Article:
Frame fields in general relativity.
In this article, as an example, they show how tetrads can reexpress the Schwarzschild metric and how one can check if the observers are inertial non-spining frames using the Ferm... |
In Griffiths' Introduction to Electrodynamics problem 10.25, I am asked to draw a "triangle diagram" illustrating the relationship between (1) the sources $\rho$, $\mathbf{J}$, (2) the fields $\mathbf{E}$, $\mathbf{B}$, and (3) the potentials $V$, $\mathbf{A}$. However, the question explicitly leaves out the arrow that... |
I'm using python to calculate the Lagrange points of the Sun-Earth system. I started assuming that - for $L_1$ at least - the sum of the gravitational acceleration towards the Sun and the centripetal acceleration towards the Sun should balance with the gravitational acceleration from the Earth:
$$
\frac{GM_\odot}{r^2} ... |
Are there any obvious (ideally physically reasonable) examples of qubit channels that give rise to non-singular Choi states?
I've been exploring the Choi state of a variety of qubit channels but find that all of the obvious targets (specifically, the amplitude damping, depolarising and dephasing channels - if proofs ar... |
According to Ehrenfest's theorem, the expectation values of observables such as position ($x$), momentum ($p$), etc. behave not only in a deterministic way but in fact in a classical way. Therefore, would it be of any interest to study Quantum Mechanics by applying the classical formulation to the expectation values? I... |
My question is simple, how can the theory of finite-sized elements (Planck-sized elements) in spacetime be correct, when you find the number $\pi$ in the Schwartzchild representation of the black hole, which implies that the black hole space-time curvature is composed of infinitely many space-time elements, as $\pi$ is... |
Let $p$ be the pressure in the center of a volume.
If $\delta\,x$ is the volume width, then the pressure on the wall can be expressed as
$$p+\frac{\partial\,p}{\partial\,x}\frac{\delta\,x}{2}$$
My question: Why is that? More precisely:
Which assumption about the pressure must be applied in order to be able to carry ou... |
Suppose we have a bar with non-zero mass inside a hemispherical bucket fixed to the ground. Suppose, too, that there is friction between the bar and the inner spherical surface of the bucket. Part of the bar is outside the bucket. Why, when the bar is about to tip over, is the normal force of the bucket on the lower ed... |
A dumb question:
When we do tensor products on angular momentum quantum numbers, for example in a decay:
\begin{equation}
A \rightarrow B+C+D
\end{equation}
Then
\begin{equation}
J(A) = J(B+C+D) = J(B) \otimes J(C) \otimes J(D)
\end{equation}
Where are we accounting of the possible angular momentum between the decay p... |
If I magnetize a ferromagnet in an coil this ferromagnet will get accelerated towards the center of the coil. And even more so, after reaching the center of the coil, the ferromagnet will get decelerated, while some magnetic properties of the ferromagnet remain.
Why does this happen?
|
Consider a free theory and let $P^\mu = (H, \mathbf{P})$ be the 4-momentum operator. Since $P_\mu P^\mu = m^2$ is a Lorentz scalar, we get the relation $H^2 - |\mathbf{P}|^2 = m^2$. Here $H$ must be an eigenvalue $E$ of the Hamiltonian so that the momentum is on shell. With this requirement we get that the spectrum of ... |
I am trying to develop a simple conceptual explanation for why ball bearings are so effective, but I am not sure if I am on the right track.
My short explanation is that a ball bearing allows us to trade a coefficient of kinetic friction for a coefficient of rolling resistance, and coefficients of rolling resistance ar... |
The movement of holes means the movement of electrons in opposite direction, so in Hall Effect the particles on which force is applied finally must be electrons, so there must be no positive charge appearing in this scenario.
|
Intuitively I'd expect a nuclear reactor to produce gamma and neutron radiation powerful enough to knock hydrogen atoms/nuclei (or electrons) off $\rm H_2O$ molecules, some of which could recombine into hydrogen/oxygen gas. The web is saying this doesn't happen. Why not?
|
I've been trying to solve the tight binding for a kagome lattice. The thing is that I find a cubic equation and have no idea on how to solve it. There's this article though (https://arxiv.org/abs/2310.05455), and on page 3 he states the solutions are $t\left(1\pm\sqrt{2\sum_i\cos k_i+3}\right)$ and $2t$. Working on it ... |
The study of transmission lines is based on the existence of electromagnetic waves that propagate through the dielectric between conductors. This question is to identify which is the electric field that composes these waves together with the magnetic field.
Variable currents cause excess charge in the conductors, which... |
Denote the partition function of a single particle by $\zeta$. The particles of one type of reactant in a chemical reaction are normally indistinguishable. The partition function of $n$ number of a single reactant is $\frac{\zeta^n}{n!}$.
Suppose now the particles are all distinct. The corresponding partition function ... |
Light hitting a surface impart a force on the surface, often called "radiation pressure". My question is, given a perfectly reflective surface, if light hits it at 90° to return in the opposite direction, how large is this pressure, expressed as a fraction of the energy in the light?
(Edit: don't take this question as ... |
I'm currently taking a quantum mechanics course in university and our professor introduced us to the Michelson Interferometer (or at least what I believe is an apparatus based on it), where a light beam is incident on a 50/50 beam splitter. I've drawn the following diagram to show what happens according to our professo... |
How many solutions are there for Maxwell's equations? (Or rather, is there a finite number of them?)
Regardless of how many solutions to these equations exist, could we claim they form a group? If so, what properties would it have? To answer the former question, I believe said solutions would fit quite nicely into th... |
Particularly given the fact that heat can propagate through a vacuum in the form of infrared radiation. But is the modern theory of heat based on the notion that heat in the matter(regardless of its phase or density) is essentially infrared photons being exchanged by molecules(or atoms in the case of a pure element or ... |
I am a sophomore taking an Electromagnetic Theory class using Griffiths. When working on the problems in the text I sometimes encounter integrals that are quite involved at least compared to what I am used to doing. Our professor recommended that we use Mathematica to do them for us. My only worry with this approach is... |
Imagine an object with internal particulate velocities $v_{i, internal}$ relative to the center of mass frame for each mass $m_i$ in two situations: one in the center of mass frame, and one where the center of mass is moving with some linear velocity $v_{cm}$.
Naturally, in the center of mass frame, the total kinetic e... |
We all know from a course on electrostatics that the electric field inside a perfect conductor, placed inside a static electric field, is zero. Now imagine the same perfect conductor is connected to a DC voltage source by perfectly conducting wires. What is the electric field inside the conductor in such a situation?
S... |
If I have 3 capacitors in series connected as shown- C1=C2=C3=C)
And let a charge 'Q' is on all 3 capacitors.
Then if a question is asked 'What is total charge in the circuit?'
Why '3Q' is the wrong answer while 'Q' is correct.
A reasoning could be that when a equivalent circuit is drawn it has Q charge with $C_{eq}$ a... |
Antimatter is just ordinary matter but with opposite electric charge.
Scientists have created only a handful of antihelium-4 in the LHC.
I am wondering if the half-life of, say, antiRadium-226 is around 1600 years as it is for Radium-226. Have we measured the half-lives of any antimatter atoms?
|
What I have so far gathered is a mathematical explanation.
Since for an adiabatic process, $pV^γ=$ constant, for a unit change in pressure, change in volume would be very less. Therefore, if compared to an isothermal process, the adiabat will be steeper.
But what is the theoretical explanation for this? And why does th... |
Positronium is an atom with one electron and one positron. It's mass is 1.022MeV which is almost twice the electron mass: The ground-state (1S orbital) binding energy of -6.8eV reduces the total mass ever so slightly.
The ratio of mass to binding energy is very close to $8\alpha^2$ where $\alpha$ is the fine structure ... |
I want to make sure that I understand the concept of reference frame in Minkowskian spacetime.
Suppose that $(\mathbb{R}^4, \eta)$ is $4$-dimensional Minkowskian spacetime. Then what we call "reference frame" would be a choice of orthonormal basis vectors $\{e_{0}|_{p}, e_1|_{p}, e_2|_{p}, e_3|_{p}\}\subset T_{p}\math... |
Standard definition for the spin coherent state (CSS) for the system of $N$ identical particles reads
$$
|\theta, \phi\rangle = \bigotimes\limits_{k=1}^{N} \left[ \cos\frac{\theta}{2} |0\rangle_k + e^{i \phi} \sin \frac{\theta}{2} |1 \rangle_k \right],
$$
where $|0 \rangle$ and $|1 \rangle$ are the eigenvectors of the ... |
In the orthodox interpretation of quantum mechanics, the following three assumptions are made (please correct me if I am wrong):
Every physical system is completely specified by a state $\lvert\psi\rangle \in H$
The state of two systems is specified by a point in the tensor product space $H_{1} \otimes H_{2}$
An isola... |
The classical Yang-Mills equation in the presence of a source $J^\nu(x)$ can be written as
$$
\partial_\mu F^{\mu \nu} - i g [A_\mu, F^{\mu \nu}] = J^\nu (x),
$$
where $F^{\mu \nu} = \partial^\mu A^\nu(x) - \partial^\nu A^\mu(x) -ig [A^\mu(x),A^\nu(x)]$, and $A^\mu(x) = t^a A_a^\mu(x)$ with $t^a$ as the generators of t... |
There are interesting non-trivial examples of spacetimes which are asymptotically flat at null and spacelike infinities. For example, the Kerr family of black holes satisfies these conditions. However, another definition of asymptotic flatness is asymptotic flatness at future timelike infinity. Minkowski spacetime is a... |
I was told that a canister of compressed air gets cold because of the ideal gas law, you are lowering the pressure and since the density of air is the same, the temperature of the can gets cold. I was trying to see this mathematically and I became confused. Can someone please help me with the intuition.
The ideal gas l... |
Wikipedia says this about optical tables:
Many optical systems require that vibration of optical elements be kept small. As a result, optical tables are typically very heavy and incorporate vibration isolation and damping features in their structure. Many use pneumatic isolators that act as mechanical low-pass filters... |
Is it possible to have a monochromatic wave which is incoherent? On the one hand, it could be obtained by irradiating a laser beam on a strongly scattering medium like white paper. But on the other hand, once the light is monochromatic its electric field is a sinusoidal wave of constant frequency and if we sum a series... |
There's an undergraduate statics problem that is about finding the lowest centre of mass of a coke can as it is emptied out (say through a weightless straw). The problem itself is not difficult and the solution is found by minimising the expression for the centre of mass: We define $H$ as the height of the can, $m_c$ t... |
I've come across the statement that 'completely random states are generically not 'physical', in the sense that they cannot be eigenstates of Hamiltonians with local interactions (in 1D)'.
Reference: Second paragraph of introduction in https://arxiv.org/abs/1506.01714
Why is it so? Aren't the spectral properties of a c... |
If a simple pendulum is in an elevator accelerating upwards, Its $T$ decreases. But why is that? The only thing that changes is the apparent weight so does $T$ depend on the weight of the bob but somehow independent of the mass. My guess is that it depends on the weight only when the mass is constant.
|
Let $\mathcal{H}$ be a Hilbert space. We define the projective Hilbert space $\mathbb{P}\mathcal{H}$ as $\mathcal{H}\setminus \{ 0\}/\mathbb{C}^*$. Then $[\Psi]=\{ z\Psi :z\in \mathbb{C}^*\}$.
On the other hand, we know that $U(1)$ acts on $\mathcal{H}_1 :=\{ \Psi \in \mathcal{H}:\langle \Psi |\Psi \rangle=1\}$. So we ... |
From quantum physics, I would expect that seeing e.g. red would excite the 564nm energy level of the Photopsin protein. I would also expect to only see (apart from some small smeering out) that we are only able to see 564nm. But based on this spectrum from Wikipedia
the opsine absorption curve is a quite spreaded bell... |
There's an example given by Brian Green, https://www.youtube.com/watch?v=XFV2feKDK9E&t=17675s
To be precise the example start at 04:56:00. In brief it is as follows:
There are two persons Gracie and George at a starting line and they are supposed to calculate how long it takes for Gracie to travel from starting line to... |
I currently have a question in a Quantum Mechanics course, which doesn't seem like it makes sense to solve. I obviously am not looking for a solution, but I want to check if it is even possible with the given information before wrecking my head any further. The question is as follows:
$\text{By evaluation of } \langle... |
I am wondering about the relation between a harmonic potential (e.g. generated by a dipole trap) and temperature. I have seen couple of times that you can express the depth of the trap as a temperature. Could someone please explain the relation there?
|
I've seen a similar set of questions on the topic in SE but none seem to satisfy me.So,the question is as follows:1)What is the relation between thermodynamic equilibrium and statistical equilibrium for a microcanonical system?
2)Is statistical equilibrium a necessary condition for thermal equilibrium?Is it sufficient?... |
Wigner symmetry representation theorem tells that if $\mathcal{S}:\mathbb{P}\mathcal{H}\to \mathbb{P}\mathcal{H}$ is a symmetry, then $\mathcal{S}[\Psi]=[\hat{U}\Psi]$ where $\hat{U}:\mathcal{H}\to \mathcal{H}$ is either a linear unitary operator or an antilinear antiunitary operator. But the linear unitary operator $\... |
Everyone knows that the Earth's surface is a 2-sphere, or a geoid.
Flat earthers propose that Earth's surface is a disk or some variation of that, and there is lots of discussion on why its not true that the Earth's surface is not a disk and so on. I don't believe in flat earth theory, but this gives me the following i... |
Let $e$ be a finitely matrix representable operator.
In physics, specially in quantum mechanics (QM), it is customary to define the conjugate operator $e^{\dagger}$, as the adjoint or the Hermitian conjugate which in this case is just
\begin{equation}
e^{\dagger}=\left(\bar{e}\right)^{T} \tag{1}
\end{equation}
wher... |
A time lag is always involved while observing objects. Due to this reason we can never observe the correct position of an object at a particular time. We will see it where it was some times ago. Is there any way to predict the observed position of an object at different places. For example let's consider an electron su... |
I have asked a similar question in relation to this topic, although I have been reading up on optical trapping some more and have many more questions. One question, in particular, is in relation to 'blue box' traps, as mentioned in this report here; Link
In this report and other similar reports I have read, the atoms a... |
In 2+1 dimensions of spacetime, the electromagnetic field is made up of a vector electric field and a scalar magnetic field. At each point in space, there is a magnetic field value, which we can define as positive or negative (what we would describe as "into the page" and "out of the page" in 3D space). Current moving ... |
In Fig. 4, in light cone ABC, there is what looks like the tips of a birds feathers from a wing (there are actually 10 corresponding to the primary feathers if you use this) in succession to the right of CH. Does this follow Young-Fresnel theory geometry, if so, what are then triangular tips representing? Also, I thi... |
I am running white noise bursts (with very short ramps on/off to prevent discontinuities) through underdamped resonant bandpasses which are tuned to any given $f_0$ and an underdamped $Q$.
Continuous white noise at an amplitude of $1$ if run through a completely underdamped resonant bandpass should bring that resonant ... |
I have been very confused with calculating the heat capacity when dealing with a Mean Field Hamiltonian.
The Hamiltonian I am working with describes a spin lattice of fermions in 2D. I only count the nearest neighbor interactions.
When I apply the mean field theory, of course I end up with the magnetization $(m=\frac{1... |
Suppose a particle starts at the bottom of a banked curve and is given an initial velocity perpendicular to the lower, inner radius. If there are no external forces on the particle apart from the normal with the curve (no gravity, friction, etc.), does the particle travel in a helix up and eventually off the banked cur... |
I am currently working on programing a small simulation involving two bodies, yet I find myself somewhat unconvinced by the results I'm obtaining.
Consider this particular test scenario: I have two identical masses connected by an inelastic cable. These masses are subjected to rotation induced by two forces acting on t... |
I understand that frame dragging will imbue momentum on plasma orbiting a black hole at close range.
My first question is - is this kinetic energy inserted very narrowly relative to the equatorial region of orbit? How do I say this correctly... An accretion disk would be a relatively flat pancake. However as the materi... |
For a mathematician with knowledge of tensor categories who is interested in the growing application of categorical techniques in topological phases of matter and topological order, along with their relationship to TQFTs, how can one begin delving into this topic? From what I have been able to search, textbooks on topo... |
Say a problem in which after an adiabatic process, during which we drop a mass onto a piston, we wait for equilibrium to be achieved, from a state A and B. Between a state A and B, what is the process? Is it isochoric? Isobaric?
The problem which I face doesn't specify whether the volume stays constant...
|
The two main ideas that led to quantization are Planck's solution to black body radiation and Einstein's solution to the photoelectric effect. In both cases, we are dealing with absorption and emission by materials, which are comprised of several atoms.
If an electron jumps to a different state, we'll get a photon (or ... |
I recently purchased a ''levitating lightbulb'' device where a lightbulb is made to float above a base via magnetism, but I am not sure exactly what is going on.
This device is not a Levitron, which operates on spin-stabilized magnetic levitation, whereas this one is just using changing electromagnetic fields.
The devi... |
In the 4D Maxwell's extended Hamiltonian action, I obtain the same expression of Fuentealba, Henneaux and Troessaert (see the picture), up to the term "$\partial^i\pi^0 A_i$", although my procedure is in agreement with this PSE thread. How can I obtain it?
Here, $\mathcal{G}=-\partial_i\pi^i$ is Gauss' law.
For comple... |
I'm very confused about the concept of "spin", the "inherent angular momentum" of an object. Will any object other than elementary particles acquire spin when it's completely stationary? Like a ball placed on the ground.
|
Alan Guth calls the universe the ultimate free lunch. What does he mean by this?
Does he mean that the total energy of the universe is zero? So the total energy of all particles is the negative of the total gravitational energy of these particles? If so, does this explain that the energy of the photon background radiat... |
My professor did the following derivation of the formula for the perihelion precession $\delta \phi = \frac{6\pi G M}{a(1-e^2)}$, but I am missing a factor of 2. I would appreciate if someone can help me spot the mistake, or tell me if the approach is totally wrong.
Consider the Schwarzschild metric, and compute the le... |
Are these all equivalent and is there an extension of this to other notation?
Does anyone have a clear and concise chart equating the different notation dialects?
I am also curious if there are more nuances to this or if it can be taken at face value.
|
I am a mechanical engineer currently in a university research program, and my project involves mixing bonded neodymium powder (Magnequench for those who are interested) into a polymer in order to cheaply magnetize the polymer, and then move it around using an electromagnetic probe. I am trying to model the forces on th... |
Imagine the usual twin paradox, a twin stays on Earth, the other twin leaves in a rocket reaches $c(1-\epsilon)$ speed for small $\epsilon$ and the twin turns around and goes back to Earth at the same speed. The twin that left Earth and came back is now younger than the twin that stayed on Earth.
Now suppose before lea... |
I was following the proof of the Bertrand theorem on Wikipedia, which is based on Goldstein "Classical mechanics" (2nd edition).
The explanation was clear upto Eq (3). But then it assumes Fourier series expansion in the form $\eta(\theta)=\sum_{n=0}^\infty h_n\cos(n\beta\theta)$. My question is how to verify this form.... |
In particular, how can you have both positrons and electrons if there is no "bit" to set or unset?
I hope this is not a stupid question, but if a particle has no internal structure, where can the difference between the electron and its antiparticle exist?
If it is due to something "external", like spin (if indeed spin ... |
This is a follow up of Interactions within constituents of dark matter .
I wonder about dark matter, and, naturally, compare it with our observable world.
If gravitation would be the only force acting on things, would galaxies and solar systems form, and how would the look like?
From what I understand is, that a disk c... |
I know that a charged balloon can attract a stream of water, because it is a dipole. I am wondering if a charged balloon can attract any other liquid other than water? Does it have to be a dipole? What liquids can it attract?
I appreciate any answers.
|
I saw the features of the Sun here and it has almost everything include nanojets and CME but not relativistic jets. Isn't the Sun magnetically active so why isn't it capable of shooting out relativistic jets?
|
Where one can buy a crystal for photon pair generation? Can it work with a LED to be registered with a CCD or LED is low and a laser is needed?
Thanks very much for who can help. I found a company producing BBO but they had no experience with Photon pair.
|
In classical thermodynamics compression always makes gas hotter because of the mechanical work it inputs. However, if the particle density is too high, particles will become degenerate and obey the Fermi-Dirac statistics instead. Particles in highly degenerate fermi gas can possess very high kinetic energy, but the man... |
Can two electrons co-moving in a vacuum form a combined pair if the magnetic field is stronger than the electric field? Quantum numbers are same except for magnetic value.
When electrons are first emitted they are probably moving at near light speed.
When electrons are in atomic orbits they are assumed to move at near... |
Let's say, that there is medium, where the speed of light is $10^8 \, \rm m/s$. So in that medium if there exists a particle that is moving through without any hindrance what would be the speed limit of that particle would it $3 \cdot 10^8 \, \rm m/s$ or $10^8 \, \rm m/s$? Since in vacuum the speed limit is equal to th... |
I've taken a few cracks and figuring this out myself, as a novice, with the equations $r_s=\frac{2GM}{c^2}$ and $M = \frac{4}{3}\rho \pi r^3$ but I think I'm just spinning in circles.
Is quark-gluon plasma dense enough (at almost 1 GeV/fm$^3$) to be able to form an event horizon if you have enough of it?
To calculate ... |
I have a real dumb question. If you have a drum or a pulley that's moving a weight on a wire up and down with constant velocity, then it needs to be stopped within a certain time. What is the deceleration caused by braking?
My understanding is that when lifting, gravity counteracts the lifting force. So if you'd stop s... |
I am working on the course MIT Quantum Physics I, Spring 2016. I am stuck in the following problem:
Question: In a classical universe, we might try to build a hydrogen atom by placing an electron in a circular orbit around a proton. We know that a non-relativistic accelerating electron radiates energy at a rate given b... |
I have an interesting question. I tried to analyze the equivalent spring constant of a multiple spring system.
When multiple springs are in parallel and have the same spring constant, all the springs compress/extend by the same distance when a force is applied. Hence, the equivalent spring constant is simply the applie... |
In the $q\bar{q}\to ZZ$ process, the following Feynman diagram in LO appears:
This means for each vertex, the Feynman amplitude contains a term proportional to $(g_V-g_A\gamma^5)$, which makes $D$-dimensional calculations of traces very difficult. In the paper where the figure above is from (doi:10.1016/0550-3213(91)9... |
I would like to know why gravity is said to be concentrated towards the center of an object.the same is taught for any other force like centripetal force acting towards the centre in uniform circular motion.but why on the centre
Can’t it act on any other direction or shally from all points
|
Heat can be considered as an inexact differential. Hence, we could conclude that:
there exists a path $\gamma$,such that:
$$
\oint\delta Q \ne 0
$$
Hence, $\int\delta Q\ne\Delta Q$.
i.e. $\Delta Q$ makes little to no sense.
Yet, I have seen equations where $\Delta Q$ is used. E.g. Latent Heat.
Moreover, I have seen sit... |
If the collecting area of a telescope is ∆A, and it collects light for a time interval of ∆t, do we just build a telescope with a very small ∆A and make ∆t and ∆λ very small as well?
Also, how do we calculate bolometric flux by integrating this formula?
For ∆E=nhc/λ, do we substitute λc as shown in the figure, even ... |
From my dynamics course, we were introduced to the so-called absolute angular velocity of a rigid body. Below is a short diagram:
The following equation for the velocity of point P on a rigid body is therefore:
There is also the so-called chain rule we learned from our tutorial exercises:
So after that short introdu... |
Warning: This is a highly hypothetical question.
I am bothered with Dirac's description of the system when making a measurement. Without quoting his statement (from The Principles of Quantum Mechanics, Dirac, 1930), he simply states that one of the axioms of quantum mechanics is that regardless of the current state of ... |
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