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In calculating the total kinetic energy of a macroscopic rigid body, we add the total translational kinetic energy and the total rotational kinetic energy of the constituent particles. Why is the total vibrational kinetic energy of the constituent particles left out?
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If I and a friend found ourselves in a world described by spherical geometry (as simulated in this linked video https://youtu.be/yY9GAyJtuJ0 ) how would the kinematics equations need to be augmented to describe the path and motion of a ball we tossed between us?
One thing in particular is that I'm not sure how to accou... |
If there were an interstellar spacecraft being propelled by gamma rays from electron/positron annihilation, they say it would get harder to keep accelerating it the closer it got to the speed of light because of what used to be called relativistic mass increase. But wouldn't the onboard electrons and positrons get prop... |
Consider a coherent state $|\alpha\rangle$, $\alpha\in\mathbb C$. In the context of a quantum harmonic oscillator, this is defined as the eigenvector of the annihilation operator $a$: $a|\alpha\rangle=\alpha|\alpha\rangle$.
In the Fock basis, this can be decomposed as
$$|\alpha\rangle = e^{-|\alpha|^2/2}e^{\alpha a^\da... |
As we can see from a normal spacetime diagram like below, there's an overlap of the area within the event horizon and the area outside the particle horizon. Could we detect gravitational waves from this part which is part of the "unobservable universe"?
Since light cannot travel through the early universe due to the pa... |
In the Pusey-Barrett-Rudolph (PBR) paper “The quantum state cannot be interpreted statistically” [arXiv:1111.3328v1, later published as Nat. Phys. 8, 475 (2012)] the following claim is made:
If a full specification of a system’s physical properties (λ) uniquely
determines the quantum state (|φ⟩) then the quantum state... |
Correct me if I am wrong but since refractive index is directly proportional to frequency, this would mean that higher frequencies would have higher refractive indexes i.e should bend more but i have come to know that higher energy waves like X-rays get refracted very little. Which statement is correct?
|
My question is how does having free electrons make something a conductor?
I know that the flow or movement of electrons create a current but can't you just add free electrons (such as a battery) to an insulator and a magnetic field making the free electrons move, thus creating a current?
|
On page 1 of the book "Principles of Lasers and Optics” by William Chang, the author, speaking about radiation from lasers, says that:
For devices with structures that have dimensions very much larger than the wave-length...
...we look for a simple analysis which can give us just the main features (i.e. the amplitud... |
In Spacetime and Geometry, Dr. Carroll provides a Lagrangian for Einstein's equations in vacuum assuming that the metric can be written in the form $g_{\mu\nu}=\eta_{\mu\nu}+h_{\mu\nu}$. The Lagrangian is, for reference, $$\mathcal{L}=\frac{1}{2}\left[\left(\partial_\alpha h^{\alpha\beta}\right)\left(\partial_{\beta}h\... |
The equivalence principle states that there is no difference between an accelerated frame of reference and the acceleration from a gravitational field. Since special relativity is able to describe accelerated frames of reference, why do we need general relativity in order to explain gravity?
|
In general we have,
$$-i\hbar \partial_x \psi(r) = e^{-i\frac{e}{\hbar c}\int dr
\cdot A(r)} \left(-i\hbar \partial_x - \frac{e}{c} A_x(r) \right) \psi^\prime(r),\tag{1} $$
with,
$$\psi^\prime(r) = e^{i\frac{e}{\hbar c}\int dr
\cdot A(r)} \psi(r). \tag{2} \quad$$
Here I'm assuming that the phase of $\psi(r)$ is sing... |
Spectra photometer was reported to measure luminance at given cps rate (counts per second). Is it enough data to know which luminance value it measured, given model and vendor are known?
|
I have a few questions about precession of Mercury and GR corrections. Feel free to any that you can:
GR is used to correct precession caused by Sun on Mercury by time dilation and length contraction. Why isn’t same treatment done to gravitational tugs of other planets on Mercury? Their value of 532 arcsec per century... |
The car rests on a ramp, and by a chain. Calculate the normal force the ramp exerts on the car. The car has a weight of 1500.00. The incline is an angle of 50.00 degrees. Answer in N.
I believe it should be N= 1500cos(50)since the normal force the ramp exerts on the car is equal to the component of the weight perpendic... |
Sometimes when measuring the phase difference $\phi$ between two beams (such as when measuring the refractive index of gas in a gas cell), the intensity is measured both when they are added directly and when they are added with an additional $\pi/2$ phase shift; from these two intensity measurements $\phi$ can be found... |
My understanding of Huygens' principle is, that it describes the way how a wave moves: Instead of moving straightforward, it propagates in all directions via producing secondary wavelets. 'Secondary wavelets' and 'wave's propagation' are synonyms.
But I realized that many others assume that waves move straight, and Huy... |
I am citing Wikipedia about Hubble constant....
"Hubble constant is most frequently quoted in (km/s)/Mpc, thus giving the speed in km/s of a galaxy 1 megaparsec (3.09×1019 km) away, and its value is about 70 (km/s)/Mpc. However, the SI unit of H0 is simply s−1 and the SI unit for the reciprocal of H0 is simply the seco... |
This is the classical example used in newtonian mechanics to explain centrifugal force. I understand that on the space station itself there is a centripetal force $\vec{F}_{centripetal} = \frac{mv^2}{R}$ exerted that causes it to spin, and also a centrifugal force $\vec{F}_{centrifugal} = -m \vec{ω} \times (\vec{ω} \t... |
I have a quite a simple question that is escaping me right now. The work done on any body is just the net force multiplied by the distance the force acts on it for.
For example: the work being done on a lawnmower moving some distance d taking into account the applied force and the frictional force is: (Fapplied - Ffric... |
This is an extract from Feynman. He is looking for various expressions for A to give a uniform B field along the $z$-axis $B_0$
I have noticed that if we do take r to be the vector displacement from the origin against his wishes it still produces the correct B field. Or am I wrong?
This is what I have using r as the v... |
In Special Relativity we solve the problem of the moving wire with an electrical current saying the protons inside the wire have a higher density: hence the wire is not neutral anymore (and we exchange a force caused by a B field with a force caused by an E field):
https://phys.libretexts.org/Bookshelves/University_Phy... |
If we had a way to measure the apparent distance to 13billion light year galaxies (parallax or something) what would it be? The light left the source 13 billion years ago, so it would appear much closer.
I can't find an answer and I'm hoping you know.
|
I have come across an interesting answer here on Physics SE which states that you get standing waves when you throw a rock in a lake, because of an “intrinsic property” of even dimensional waves.
“(...) waves in an even number of dimensions, such as on water, reflect back, even if the wave impedance is constant. For ex... |
I read that the air purifiers that can create negative ions also increase ionization, in theory is it possible to create a negative charge/ negative ions without creation ionization similar to waterfalls, etc.?
|
I was just wondering how the value of a spring constant would change if gravity were increased. Agreeing that gravity is 9.8 m/$s^2$, if, for example, gravity was changed to 15 m/$s^2$ with nothing else to consider in altering a spring constant, how would the spring constant change? Would it increase, decrease, or stay... |
Escape velocity is the ballistic speed required to escape from a gravitational field to infinity, ignoring any third body dynamics. The operative word here being ballistic, meaning unpowered.
In response to prior question removal:
The below reference to a Fermi Drive is a tongue-in-cheek handy
Gedanken constru... |
I was reading Dirac's General Theory of Relativity. In chapter 16, the Newtonian approximation, we start with
Let us consider a static gravitational field and refer it to a static coordinate system. The $g_{\mu\nu}$ are then constant in time, $\frac{\partial g_{\mu\nu}}{\partial x^0}=0$. Further, we must have
\begin{e... |
I am attempting to derive the effective potential for a test particle around a massive object from the Schwarzschild metric; however, an extra term has appeared in my solution compared to Wikipedia's, which I am most confused about. A quick summary of my derivation is below; why is this extra term here, and what is its... |
I'm a little bit confused with how to understand the relationships between spin angular momentum $S$, orbital angular momentum $L$, and the total angular momentum $J$ by visualizing those quantities. Classically, if we consider the motion of the Earth, I think $S$ is its rotation, $L$ would be its orbit around the sun,... |
I am reading Scott Shell's Thermodynamics and Statistical Mechanics, and I just saw this statement:
If freezing happens fast enough, to a good approximation the process can be considered adiabatic.
The author has mentioned this statement while talking about a problem regarding the spontaneous freezing of subcooled wa... |
What is the formula for a metronome pendulum?
|
I am reading Sakurai's Modern Quantum Mechanics, and I am so confused by the notations as I read the section Translation. The book throws these relations to me ($\mathscr T(\mathrm d \boldsymbol x')$ denotes the translation along $\mathrm d \boldsymbol x'$, i.e. $\vert \boldsymbol x' \rangle \mapsto \vert \boldsymbol x... |
Given an ensemble of $N$ diatomic molecules, we know that the rotational partition function is given by $$Z_r = z_r^N$$ where $$z_r = \sum_{l} (2l+1)e^{-Kl(l+1)}$$ where $K = \beta \hbar ^2 /2I$.
I want to apply this to calculate the $C_v$ for an ensemble of $H_2$ (hydrogen) molecules in the low $T$ limit and the high ... |
Let's consider a system of bead-spring with $N+1$ beads connected with $N$ springs:
The Hamiltonian of such a chain is:
$$
\mathcal{H} = \frac{1}{2} k \sum_{i=1} ^N (\mathbf{r}_{i+1} - \mathbf{r}_{i})^2 + \frac{1}{2} m\mathbf{\dot{r}}_{i}
$$
where $k$ is the spring constant, $m$ is the mass, $\mathbf{r}_{i} $ is the ... |
The Newtonian approximation of gravity is $\frac{GmM}{r^2}$. General relativity is the accurate model of gravity. But does special relativity by itself provide any update to Newtonian gravity?
I think we should arrive at some four-force called a gravitomagnetic force in SR. Is that a thing? If this, how does this SR ap... |
There was an excellent site at Kansas State University but it no longer works in most browsers. I'm looking for a replacement. The solution of energy levels for 2 to 10 individual finite quantum wells shows the origin of band theory of solids. The 10 wells are a "model" solid. This is much, much better than the Kro... |
Does a rotating magnetic monopole have an electric dipole?
It is known that a rotating electrically charged sphere possesses a magnetic dipole, so for symmetry I guess that also a magnetic monopole has an electric dipole, but I cannot prove it.
According to Wikipedia, the electromagnetic field of a particle with both e... |
I am trying to plot the Bi-stable behavior governed by the equation:
Here the parameters have given numerical values.
For a certain range of $x$ there exists three roots. Ideally two of these should be purely real and the other complex. I tried plotting it in Mathematica and from the graph it seems that for this rang... |
I was reading a paper about Wilberforce Pendulum:
https://faraday.physics.utoronto.ca/IYearLab/WilberforceRefBerg2of8.pdf
This is the potential energy of (spring+weight with moment of inertia)
$V={{1}\over{2}}kz^2 + {{1}\over{2}} \delta\theta^2+ {{1}\over{2}}\epsilon z \theta$
where $k$ is the spring constant and $\del... |
How the chemical potential is related to near boundary expansion of Gauge field?
|
I thought that direction of surface tension is along the tangent to the surface which is best explained by this diagram which I found this diagram in Wikipedia
But recently I saw in a book the diagram below
Where
I know that their direction are along the tangent to interface .... but I didn't understand why $S_{sl}$... |
I just came across this video. A styrofoam box falls out of a moving van, bounces off the road and lands back in the van.
How can the box land back so precisely inside the van?!
Usually, I would consider these type of videos as bogus. But the fact that the box is very light and that I have seen dry leaves chasing a mo... |
In this stack about deriving Lorentz transformations, the op writes an answer where he proves the relation between time in a moving frame and regular frame but I just can't understand what the logic of it is.
What I understand this is that when the rod moves, the path is altered and hence light needs a different tim... |
According to Kinetic theory, the kinetic energy of one molecule of gas is 3/2kT. Is this true for diatomic and polyatomic gases as well?
I've read that a diatomic gas has 5 degrees of freedom (3 translational +2 rotational), and according to the Law of Equipartition of Energy, each degree of freedom contributes an ener... |
With a little ingenuity, someone with DIY skills can replicate classical results such as Boyle's law, the swing of a pendulum, refraction, etc.
Without spending years of study and huge amounts of money, how can an average person convince themselves of the truth of what physicists claim about relativity, quantum mechani... |
I read about an experiment from a very reliable source (my textbook).
The basic idea is a circuit with a battery, ammeter, switch and wire. A segment of the wire is sort of a test wire. We replace the original wire with a wire of twice the length. The ammeter reading falls by half. Try it out with different length and ... |
I am trying to get some understanding of next scenarios.
Suppose we have three objects: Light source 1, Light source 2 and observer. LS1 and LS2 both emit a single photon each second with the same energy.
They are spaced like so:
(LS1)-----------------(O)-----------------(LS2)
Can you please confirm or reject my expect... |
Mass and charge are two fundamental properties of the universe. I hope you agree that they are different in that they denote different properties, but similar in that they are both fundamental. Space is, like mass and charge, a fundamental aspect of the universe. But space differs from matter and charge in that matter ... |
An Einzel lens is a device for ion optics to focus a beam of particles. It consists of three ring electrodes, with the outer ones being on earth potential and the middle one being on high voltage (see picture).
Now, due to the arrangement of the electrodes, the whole system including its electrical field is symmetric a... |
I am getting confused with what area do you use in AC generators and coils.
Let me explain:
in an AC generator, there are two coils that rotate. When using the equation - magnetic flux $= BA\cos(x)$, when the area is perpendicular in the field, the emf induced within the coils should be 0. However, I keep getting the ... |
So I've read a couple of pages and watches a few videos but at their core neither has answered this basic question.
I remember from the lecture that the prof. said that one needs a high current while the other needs a high voltage (with low current).
But I don't remember which is which and also I'd like to learn more a... |
In the book "Modern Quantum Mechanics" (by J.J. Sakurai and Jim Napolitano) page 44, infinitesimal Translation operator is given:
$\mathscr{J}\left(d \mathbf{x}^{\prime}\right)\left|\mathbf{x}^{\prime}\right\rangle=\left|\mathbf{x}^{\prime}+d \mathbf{x}^{\prime}\right\rangle$ after this, book mentioned properties of th... |
I just saw some exciting news from Tesla regarding a new battery, but I'm quite confused. As you can see on the headline of this article and the accompanying Tesla infographic:
The claim is that the battery has 5x the Energy capacity and 6x the power output. So why does it only have +16% range? I assume this is the ra... |
The following graph is supposed to present turbulent magnetic field lines along with the spatial distribution of out-of-plane electric current density.
However I am not sure I completely understand this.
Do the black line represent the magnetic field lines and the red color the current coming out of the plane?
Could s... |
Like charge, spin,etc.. Parity is an intrinsic property of the particle. As I read in Grifith's introduction to elementary particles book , he states parity mathematically but I am not able to see it physically, for vectors we invert, so what do we do for particles when applying the parity operator on them ?
|
In a recent test I had a question in which there was an LC circuit with an inductor a capacitor and a switch. According to the answer key
If switch is opened when capacitor is fully charged energy of LC system remains same.
If switch is opened when capacitor is fully discharged energy of LC system becomes 0.
I can ... |
Why is the velocity at the point of contact (between wheel and surface when the condition is rolling without slipping) with respect to the surface remains zero all the times although the center of wheel moves forward?
|
I just read about Prism Binoculars from my high school physics textbook. However, I am not able to understand how does increasing the distance light travels from the objective lens to eyepiece can affect the magnifying power of the binoculars nor was I able to look for any answers.
Thanks in advance
|
In my lab we have to calculate uncertainties in measuring devices and we are given a document explaining different uncertainties for different tools (rulers, digital stopwatches, etc.) I'm just having a difficult time understanding what the uncertainty for a measuring tape is. In the document it is explained as "the un... |
In Quantum Mechanics 2nd edition by Griffiths, he says we can get Maxwell-Boltzmann distribution as we deal with distinguishable particles. And I think ideal gas follows MB distribution; therefore, I think ideal gas is distinguishable until now.
However when I start learning thermal physics, the textbook tells me if a ... |
This is Wilberforce Pendulum that has spring & weight:
https://faraday.physics.utoronto.ca/IYearLab/WilberforceRefBerg2of8.pdf
Wilberforce pendulum is a system of a spring hanging vertically, and a weight
with moment of inertia is hanging.
The system keeps transferring vibration between the spring's vibration and the t... |
According to Newtonian gravity (in the absence of other forces or obstacles) a free electron (not moving at high velocity) should (because it has mass) fall towards the Earth's centre with the same acceleration as a hammer, feather, atom, neutron, proton, or any other massive object. (I think that General Relativity pr... |
Is it possible to analytically calculate (or verify the existence of) zero energy edge states for the SSH model in real space? This seems to be discussed in Section 1.5.2 of "A Short Course on Topological Insulators" (link, open access), but I don't follow the logic and it also doesn't seem to quite be the SSH model.
|
My AP students are learning 2D kinematics, and it got me in the mood to play around with projectiles WITH air resistance, just for fun because we always neglect it, and so that I can maybe show them when the unit is over.
I understand the flow of the process for deriving the formulas, and I found a site that goes throu... |
I read this news about a Jupiter sized planet orbiting a white dwarf.
It is still puzzling to the scientists that how it remained as a single piece.
NOTE: I went through the Astro.SE link given in the comment section by Jon Custer. But it doesn't seem to answer these two questions.
Is it theoretically possible? Can it... |
The Quantum Geometric Tensor is given by
$$
\begin{split}
Q_{\mu\nu}=\langle\partial_{\mu}\psi|\partial_{\nu}\psi\rangle-\langle\partial_{\mu}\psi|\psi\rangle\langle\psi|\partial_{\nu}\psi\rangle
\end{split}
$$
I wanted to confirm whether for the $SU(2)$ coherent state
$$
\begin{split}
|z\rangle=\frac{1}{(1+|z|^2)^j}\s... |
Question:
Show that the line of action of the buoyancy force on an arbitrarily shaped body submerged in a liquid passes through its center of mass
My observation: I know that buoyant force is equal to the weight of the submerged body. But how can I proceed further?
|
Consider a monochromatic, uniformly polarized, EM wave:
$$E(x,y,z,t)=\tilde E(x,y,z)e^{iwt}$$
If on a certain plane $z=z_1$ the field $\tilde E(x_1,y_1,z_1)$ is known, we can find $\tilde E(x,y,z)$ on a plane $z$ using the Fresnel-Kirchoff integral:
$$\tilde E(x,y,z)=\frac i \lambda \iint_S \tilde E(x_1,y_y,z_1) \frac ... |
In scattering theory, the transition rate is expressed in terms of the transition operator
$$\frac{2\pi}{\hbar}\rho_f|T_{fi}|^2 \,,$$
and the cross section is obtained by dividing the transition rate by the incident flux $F_{inc}$.
In my Quantum Mechanics class, the teacher proceeded by using "infinite volume normaliza... |
**I have searched on google,youtube everywhere about by topic but there no relevant content.
I need a help in finding angular momentum about point C as shown in diagram.Body is performing pure rolling motion.
Please also provide proof for angular momentum abot moving point.
I know that angular momentum about a point i... |
In many books it is written that the optic axis of a crystal is a direction rather than a single line! I really cannot understand what is the necessity of the direction and why I cannot say that it has the opposite direction rather than what is defined in the book?
|
In this article by Matt Strassler, he says "A struck quark, like any accelerated particle, will radiate. A suddenly accelerated quark will radiate many gluons. So what actually emerges at the edge of the proton is not a fast quark but a collection of fast gluons along with the fast quark. The shape of the jet is act... |
Metals like copper, gold,silver hold the lowest spot in chemical reactivity series ie; they show more tendency to get reduced than any other metal; but in terms of electrical conductivity they hold the highest spots. I seek for a well defined relation between activity of metal and it's electrical conductivity and also ... |
I was working on a question where there was a circuit and the switch was open, there was one capacitor and one resistor. It said: immediately after the switch is closed, what is the current in the circuit, the pd across the resistor and the pd across the capacitor.
The answer was: the current was 6A, the pd across the ... |
I have this generator
$$ Z(J,\lambda)=\int D\varphi e^{ i\int \!d^4x\,\{ \frac{1}{2}[(\partial\varphi)^2-m^2\varphi^2 ]-\frac{\lambda}{4!} \varphi^4+J\varphi \} } .\tag{11} $$
Which I first expand in $J$ to get
$$\begin{align} Z(J,\lambda)&=\int D\varphi e^{ i\int \!d^4x\,\{ \frac{1}{2}[(\partial\varphi)^2... |
From Braddick's The Physics of Experimental Method (1963):"It should be remembered that the number of significant figures in a number $y$, and one derived from it, say $e^y$, are not always the same. Thus if $y=1.32\times 10^{-2}$ (three significant figures) then $e^y=1.1034$ (five significant figures)".
What is the ra... |
Thanks for any help. Here is the momentum example: Alice obtains a fire extinguisher which she holds firmly on her office chair.
Suppose Alice opens the nozzle of the fire extinguisher so that it ejects gas at a constant rate (mass per unit time) and constant speed. How will Alice move? The answer for the example was ... |
So I know non-uniform velocity as, "Non-uniform velocity is when an object covers unequal distance in equal interval of time in a particular direction or covers equal distance in equal interval of time but changes its direction" (am I correct?) and acceleration is "rate of change of velocity per unit time". So my quest... |
I learned recently how to compute the basic generating functionals. My next goal is to understand how I can use them to compute effective interactions. I started with the Yukawa interaction because it is quadratic and, a priori, exactly solvable. On the other hand, the examples in books and lecture notes are in the g... |
I'm reading Thermodynamics and an Introduction to Thermostatistics by H. B. Callen. Near the end of section 1-4 he writes:
Only differences of energy, rather than absolute values of the energy,
have physical significance, either at the atomic level or in macroscopic
systems. It is conventional therefore to adopt some ... |
A bungee jumper of mass $75 kg$ is standing on a platform $53 m$ above a river. The length of the upstretched bungee cord is 11m. The spring constant is $65.6 N/m$. Calculate the jumper's speed at $19 m$ below the platform on his first fall.
I'm able to solve it using conservation of energy $E_g= E_k+E_e$ to get correc... |
I stumbled upon a problem when trying to explain how a spectrometer with a prism works based on geometrical optics.
I started from the basic example of image formation based on refraction as it is given in the figure below.
What I next did is to see if the distance $h_1$ depends in some way on the angle $i$ and after ... |
I'm a student in physics and I was wondering how I would go about solving for tension for both string A(left) and string B(right). Thanks for the help!
|
The equations of motion for a classical field $\phi$ can be obtained using the Lagrange:
$$ \frac{\partial \mathcal{L}}{\partial \phi} - \partial_\mu \bigg ( \frac{\partial \mathcal{L}}{\partial(\partial_\mu \phi)} \bigg )=0 \tag{1}$$
A simple Lagrangian: $$ \mathcal{L} = \frac{1}{2} \partial_\mu \phi \partial^\mu \phi... |
It's easy to take a quantum state represented on the Bloch sphere and rotate it around an arbitrary ray emanating from the origin. On the other hand, we can never use a unitary matrix to get a reflection preserving one coordinate and negating a third. Intuitively, why is this the case? Unitary matrices are isometries o... |
I have read the other question (How can a Population III star be so massive)... but it does not answer my question.
R136c Is a Wolfe-Rayet star. It is 230 the mass of our sun.
My question is this: This star is well passed the Eddington Limit (though if it is a hypothetical metal free star it could be within the Edding... |
Potential energy of a system is the energy possessed by the system by virtue of the configuration of different elements with respect to one another. It can be given any arbitrary value, by adding or subtracting a constant value.
But can we do the same to kinetic energy? Is it possible to add a constant to the definiti... |
I've been puzzling over this for a couple days now and I can't find an answer on the internet.
I have two wedges (inclined planes) facing each other (in the image above) and one of them (the black triangle) is fixed in place and the other can move. I apply a force F to the moving wedge. I want to know two things: (1... |
I've heard that a qudit is a unit of quantum information described by a superposition of $d$ states (more general than qubit). However, I haven't found a formal introduction about what it is and how it might be more powerful than qubit. Also, we know that the two states $|0\rangle$ and $|1\rangle$ in qubit could corres... |
In doing instanton problems or when connecting quantum field theory to statistical mechanics, I often see people trying the Wick rotation trick by defining an imaginary time $\tau\equiv it$. So, in this case, we should make sure that $\tau$ is imaginary, right? However, I often see places where people seem to handle $\... |
I have read somewhere that Work Energy Theorem can be applied even from non-inertial frame by adding work done by pseudo force.
I further think that we need to take Kinetic Energy with reference to this frame for the theorem.
My question:
Is my thinking correct?
I find it a little absurd that "energy depends on frame... |
I simulated a hyperspherically symmetric wavefunction for the case of $V=-\cos(r)$, in which $h=1$, and $m=1$ and the number of spatial dimensions is $4$.
I charted the integral of the square of the absolute value of the wavefunction multiplied by $r^3$
I find that in both charts the integral looks the same even thou... |
I would like an explanation to how this Lagragian partial derivative was taken (eq. 3). This probably is more suited for the math Stack Exchange, however this is for a physics course which is why I am posting here. Based on the definition of a Taylor expansion:
I don't understand how or why it is only the partial is w... |
I recently tried to derive the rocket equation using conservation of momentum, and did not get very far; was wondering what I am missing. Here's my attempt:
Let's say that over some small time $dt$, the rocket ejects $dm$ mass at speed $c$ going the opposite way, and speeds up by $dv$ as a result. So,
$$p_i = mv$$
$$p_... |
I really need some help on this problem, as I seem to be extremely close to the answer, but am only differing in one spot. Here is the problem:
The function $u(f, T)$, where $$u(f, T)=\frac{8\pi hf^3}{c^3}\frac{1}{e^{hf/kT}-1}$$ is the distribution of blackbody radiation in terms of frequency $f$ and temperature $T$; $... |
In the figure above in which the sphere rolls without slipping down an incline, why is static friction directed upward? Static friction is meant to oppose impending motion so it should oppose the object's tendency to slide, and gravity would cause it to slide down in the absence of friction. Doesn't this mean that fri... |
Imagine that you, unfortunately, fell into a black hole. For external observers, you would slowly go closer and closer to the event horizon. Then, when you reach the event horizon, you would appear to be frozen there and get red-shifted for an external viewer.
Since it takes infinite amount of time to enter the event ... |
I'm reading through Guth's 1980 paper "The Inflationary Universe" and I have one simple question (so far)...
He gives this definition of the density parameter:
\begin{equation}
.01 < \Omega_{p} < 10\tag{1.1}
\end{equation}
where
\begin{equation}
\Omega \equiv \frac{\rho}{\rho_{cr}} = (\frac{8\pi}{3})G\rho/H^{2}\tag{1.... |
I was reading about tensors and especially stress tensors in Feynman lectures on physics
Which is on the webvsite enter link description here
While reading the “31-6. The tensor of stress”, I was a bit confused.
In the book it states that each tensor component corresponds to a component of the force per unit area that... |
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