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I was wondering whether there is an equation that enables me to calculate the reflection, transmission, absorption and polarization, when the electric field everywhere is given?
Consider this: You have solved the full Mie scattering process, so incident field, the field in the sphere and the scattered field are known. ... |
Seeing an interesting BBC article today at http://www.bbc.co.uk/news/science-environment-23514521 about the Longitude Problem, I wondered if it could have been solved, in a way practical at the time (the 18th century), by any means other than the solution eventually found.
So if fanciful, but possibly entertaining and ... |
I have a question about equivalence principle in quantum mechanics.
Consider a Schroedinger equation under gravitional field
$$\left[ - \frac{1}{2m_I} \nabla^2 + m_g \Phi_{\mathrm{grav}} \right]\psi = i \partial_t \psi \tag{1} $$
where $m_I$ and $m_g$ are the inertia and gravitational masses, respectively. $\hbar=1$ un... |
This is quite large homework where I 1st had to normalize the wavefunction $\psi = Axe^{-x^2/2a}$ and I got a constant $A=\sqrt{2/(a\sqrt{\pi a})}$.
How do I calculate the probability now for the interval (-0.1nm , + 0.1nm) if $a=1nm^2$?
I first tried to calculate the normalisation factor but the units are weird... i... |
I am doing some research to see if there is a simple equation (or an equation that can be simplified) to estimate the volume of a drop of liquid falling due to gravity based upon the approximate flow rate, and perhaps the viscosity/surface tension of the fluid.
Basically this is a drip chamber fluid set for delivering ... |
Is there any reflection of light that enters a new medium at a 0° angle, if the electric field is such, that it is completely in the plane of the double layer?
|
I read somewhere that it is about one percent of the mass, but I find this too high.
Also I have done some calculations, for example, the Tsar Bomba was 50 MT bomb and weighed about 27 tons. Although I don't know how much exactly fusion fuel was used, I think it is safe to assume that a large percentage of this 27 tons... |
I read somewhere that the earth has to be smaller than 1 cm to become a black hole, according to Schwarzschild. Since big bang came from a singularity, I am wondering, is there any minimum volume for anything?
|
A solid right cylinder of rock core is surrounded by four rods made of mild steel (all-thread rods). The rods are placed equidistantly around the core in a square formation. The tops and bottoms of the four rods are fixed to the top and bottom rigid plates, but the rock is just fitted snugly between the top and bottom ... |
Do fermion and scalar running masses run in the same way? Specifically, what are the qualitative differences in the mass beta functions for, say, scalar $\lambda\phi^4$ field theory and the fermion masses in QED?
Next, is there some obvious intuition for whether the masses should get bigger or smaller in the UV? Sinc... |
How does the Rayleigh scattering intensity depend on the polarization angle of the incident, linearly polarized light, and the observation angle in three dimensions?
|
I'm having a difficult discussion with a colleague because I'm running heat flow simulations for a small heater (5 mm^2 area), and I insist that if we're going to run more electrical power through the heater then we should modify the convective coefficient. However this person claims that even though we are running dif... |
I'm having some troubles with the trilinear soft couplings of the MSSM RGEs. I've used the ones written in Martin's supersymmetry primer and I run them using mathematica, if I do so without taking into account the soft trilinear terms (by putting them to zero at all scales and not considering that they get generated ev... |
Given the differential equation
$$ -\hbar^{2}D^{2}y(x)+ae^{bx}y(x)=E_{n}y(x) $$
here $ D=d/dx $ is the derivative,
are there examples in physics where this potential appears ?? I know how to solve it but I do not know pratical examples where the exponential potential appears.
the solution is given by
http://www.wolfram... |
So this is the question that's been bothering me:
Say you have a simple rigid body in space that is at rest or traveling with only translational motion at a constant speed. Say that the body is something like a rod and it's not rotating. So, at some point, an external force is acted on the rod, just for an instant and ... |
In chapter 7 of Peskin and Schroeder they define the field strength renormalisation $Z$ for a quantum field to be the residue of the Fourier transform of the correlation function
$$\langle \Omega | \phi(x)\phi(0) | \Omega\rangle$$
They go on to refer to $Z$ variously as $Z_1$, $Z_2$ and $Z_3$ at different points in the... |
I have a super basic and stupid question about the Lorentz invariance of the Polyakov action (cannot skip the disclaimer..)
$$S_p[X,\gamma]=-\frac{1}{4 \pi \alpha'} \int_{-\infty}^{\infty} d \tau \int_0^l d \sigma (-\gamma)^{1/2} \gamma^{ab} \partial_a X^{\mu} \partial_b X_{\mu} $$
I may write the action as (using metr... |
I have a wavefunction ($a=1nm$):
$$\psi=Ax\exp\left[\tfrac{-x^2}{2a}\right]$$
for which I already calculated the normalisation factor (in my other topic):
$$A = \sqrt{\frac{2}{a\sqrt{\pi a}}} = 1.06\frac{1}{nm\sqrt{nm}}$$
What I want to know is how to calculate the expectation value for a kinetic energy. I have tried ... |
Show that: $$\int _v \vec{J} dV = \frac{d \vec{p}}{dt}$$
Here's my attempt: $$\vec{p} = \int _v \rho \vec{r} dV \rightarrow \frac{d \vec{p}}{dt}= \frac{d}{dt} \int _v \rho \vec{r} dV = \int _v \frac{\partial \rho}{\partial t}\vec{r}$$
Because of the fact that $\nabla \cdot \vec{J} = - \frac{\partial \rho}{dt}$ we have... |
I've been reading an introduction to quantum mechanics online, and while constructing the Schrodinger equation for a free particle, the equation $i\hbar \frac{d \Psi}{dt}=\hbar\omega\Psi$ is obtained.
It is then explained that if $i\hbar \frac{d}{dt}$ is considered as an operator, then the equation means "that when it... |
A smooth parabolic tube is placed with vertex downwards in a vertical plane. A particle slides down the tube from rest under the influence of gravity. Prove that in any position, the reaction of the tube is equal to $$2w({h+a})/\rho$$ where $w$ is the weight of the particle, $\rho$ the radius of curvature of the tube,... |
Considering that light is in the 400-800 THz range, if you had an electrical oscillator that ran at that frequency connected to an aerial of some sort, would the antenna emit visible light, in the same manner that radio waves emit radio "light"?
We have specialized transistors that can run at many hundreds of gigahertz... |
Can someone show me how the Lorentz transformation can be derived from the metric equation:
$s^2=c^2t^2-x^2$
|
In what way does the rotating gyroscope help in changing the orientation of the international space station in space ?
Is there any other way to change the the orientation of ISS ?
|
Is there any scientific experiment that can lead us to conclude we live in 3 spatial dimensions without the premise of the conception of limited dimensions?
Thank you all who helped in the improvement of this question (which was not clear at first).
EDIT:
I know that this can be a little philosophical, but it is also ... |
I have just discovered that if I rotate my left spectacle lens about the vertical axis by 10 degrees in one direction, the vision in that eye becomes much crisper.
Note that the sphere and cylinder prescriptions in the (unrotated) lens were confirmed yesterday by an optometrist as being the best I could get -- but simp... |
does anybody here know an analytical approximation of the bonding hydrogen orbital MOLECULE?
I am looking for a good approximation to this orbital, that might be in some textbooks to get an impression how this whole concept of bonding antibonding works?
|
For the calculation of force on one of the two equal(in magnitude, opposite in sign) point charges separated by $r$ with a dielectric slab of dielectric constant $K$ and width $d$ in between, the formula presented in many books is:-
$$F=\frac q{4\pi \epsilon_o (r-d + \sqrt{k}d)^2}$$
This means that the force between t... |
We know that i)avg speed of A Hamster is 30km/hr.
ii)Avg mass of hamster is 1.5 kg.
From the above info:
Kinetic energy=1/2 X mass X velocity^2
So,
K.E=1/2 x 1.5 x 30 x 30
=1/2 x 3/2 x 900
=675
=675 J per hr.
In one second,=675/3600
=1/5 j/s
but power needed is 15j/s to light a CFL.
7... |
I have wondered for a long time how elliptical orbits can work. It seems awkward for a freely-moving object to come very close to a source of gravity and then return to the exact point where it started. I started to wonder even more after playing with the Box2D physics engine recently and finding that when I caused one... |
While on an expedition to a lake, it was noticed that the wind speeds gusted violently in seemingly periodic wakes and the proposed explanation was Von Karman vortex shedding off of nearby mountains that the lake was in the lee of.
Therefore I am attempting to calculate the amount of influence that a Karman vortex str... |
I'm not sure if this is an acceptable place to ask this question, as it may have more to do with the biological workings of human eyes than with the physical properties of light, but I'd rather hear a physical explanation than a biological one (if one exists).
Essentially, we often describe the visible spectrum with a... |
Feynman mentions in his lectures:
...the concept of a molecule of a substance is only approximate and
exists only for a certain class of substances. It is clear in the case
of water that the three atoms are actually stuck together. It is not
so clear in the case of sodium chloride in the solid. There is just an
... |
Is there a physical method to prove for example when the zeta regularization of a series
$$ 1+2^{k}+3^{k}+............= \zeta (-k) $$
gives the correct result: Casimir effect, vacuum energy and when does it 'fail'?
For example we plug the zeta regulator inside the renormalization group equations and this group tells us... |
I'm having a party.
Suppose I'd like to have a fridge full of cold ($6~^\circ\text{C}$ or below) beer bottles, in as short a time frame as possible. The fridge indicates that it is targeting (and presumably currently at) $4~^\circ\text{C}$. All the bottles are currently at $30~^\circ\text{C}$, which is the temperature ... |
The Helmholtz equation is expressed as $$\nabla^2 \psi + \lambda \psi = 0$$. This equation occurs, for eg., after taking the Fourier transform (with respect to the time coordinate) of the wave equation in free space. While this equation for the case of $\lambda$ real is reasonably well discussed in the literature, the ... |
I am learning about electricity and magnetism by watching MIT video
lectures.
In the lecture about Gauss's law, while trying to calculate the flux through a sphere with charge in it, the lecturer states that the direction of the electrical field is radial, since it is the only preferred direction that there is (since t... |
My question relates to the third MIT's video lecture about Electricity
and Magnetism, specifically from $21:18-22:00$ : http://youtu.be/XaaP1bWFjDA?t=21m18s
I have watched the development of Gauss's law, but I still don't quite
understand the link between Gauss's law and Coulomb law: How does
Gauss's law change if Coul... |
I'm well aware that the default answer to this textbook default question is "it doesn't work", but still, I believe it does.
To cool the insides of the fridge, the compressor must do work, and since the efficiency isn't 100% you are constantly warming the whole room to cool it's insides, the winning move here is simply... |
According to this database:
http://www.ga.gov.au/oracle/nuclear-explosion.jsp
Since 1962, 99% of USA Nuclear tests was underground.
Since 1964, 99% of Soviet Nuclear tests was underground.
Is it ecologies nuance, or what?
|
Please bear with me, as I'm not in the field of physics, this question may seem a bit simple.
The scenario is the following;
A specific stable orbit radius of a small body, say a satellite, to large body, say a planet, is known.
My questions then are;
Is the velocity of said body a single value, or is there an inte... |
I understand that, due to the Doppler effect, different frames of reference moving at different velocities relative to each other will measure different photon frequencies and hence energy. The amount of energy measured in a frame of reference is specific and unique to that frame. That was answered in this question.
... |
Is the main idea of femtosecond or attosecond lasers is to achieve the high energy or do we have any other parameters achieved by ultra-fast lasers ?
|
Is it possible to use the sawtooth shape diffraction grating instead of rectangular grating
if yes then which parameters will affect at the output ? Secondly, what is special in blaze grating comparison with rectangular shaped diffraction grating ?
|
I'm deeply interested in understanding delayed choice eraser experiment. Although I understand the experimental results, the retro causality is causing a big headache.
From what I understand, the hidden variables theory is a no - no, due to experimental verification of the Bells inequality...
A recent PDF that I came a... |
Is there a retarded potential concept in gravitational field similar to electromagnetic radiation?
|
I'm trying to understand charge renormalization in QED. I know that one can write the full photon propagator as
$$\frac{-i\eta_{\mu\nu}}{q^2(1-\Pi(q^2))}$$
where $\Pi$ is regular at $0$. Obviously this leads to a running coupling.
However I don't see why we also have to renormalize
$$e \mapsto \sqrt{Z}e$$
where $Z$ is ... |
can we use the tools of renormalization of casimir effect to get finite results for any divergent series in QFT?
for example let be the divergent series $ \sum_{n=1}^{\infty}n^{l} $ for positive 'l' then instead of the sum we interpretate this as the difference
$$ \sum_{n=1}^{\infty}n^{l}e^{-n\epsilon}-\int_{0}^{\infty... |
I have a pretty simple homework question, but I can't rap my head around it.
In the question a swimmer of $55 \mbox{ } \mathrm{kg}$, jumps off a stationary raft of $210\mbox{ }\mathrm{kg} $. The swimmer jumps off the raft with a speed of $4.6 \mbox{ } \mathrm{ms}^{-1} $. I need to... |
I'm analyzing the experimental data obtained during Frank-Hertz experiment (conducted with Hg atoms):
Accelerating voltage values were multiplied by 0.1 during measurement (i.e. the mean value of energies differences if not 0.508 eV, but 5.08 eV). The output voltage was measured on resistive load of the anode, therefo... |
I am going over Coulomb's law and there is something that is a bit
confusing for me:
According to Coulomb's law, if I have a charge $q_{1}$ at a point
$\vec{r_{1}}$ and a charge $q_{2}$ at a point $\vec{r_{2}}$ then
the force that the first charge applies to the second charge is given
by
$$
F_{1,2}=\frac{Kq_{1}q_{2}}{... |
Suppose we create very large spherical body by using gamma rays generator and they will concentrate on a single point at the centre of sphere.We will place this spherical body thousands of kms above the sun so that it can draw energy from sun.Can the centre of the sphere create a Mini Black hole by the energy from the ... |
I have a question the variation of the Polyakov action, related to this Phys.SE post.
For Polyakov action
$$ S_p[X,\gamma]=-\frac{1}{4 \pi \alpha'} \int_{-\infty}^{\infty} d \tau \int_0^l d \sigma (-\gamma)^{1/2} \gamma^{ab} \partial_a X^{\mu} \partial_b X_{\mu}.$$
Consider the variation (p. 14 in Polchinski's string... |
This is an exercise of my last exam. Since I couldn't find anybody who solved it or knows how to, it would be really nice if somebody could tell me if my thoughts on it go into the right direction.
Two harmonic Oscillators can be described by the Hamiltonian
$\hat H_a + \hat H_b + \hat H_c$
where
$\hat H_a = \hba... |
I was wondering whether there exists a theory that describes Mie Scattering for spheres that have a constant dipole moment. Since there are theories that describe Mie scattering in the case of a charge, this might exist too?
|
Just starting to learn physics. Now reading about constant motion and after this paragraph
I have a task:
Boy with growth of 1.5 m runs at a speed of 3 m / s in a straight line, passing under a street lamp, hanging at a height of 3 m. Show that the shadow of his head moves uniformly, and find the speed of the movement.... |
The proof of the No-Cloning Theorem states "By the linearity of quantum mechanics, ..." -- Could someone please give me a rough sketch/outline of what this means? Does it have to do with the Hilbert Space that wave functions live in?
I apologize if this question isn't specific enough, I just wanted to fully understand... |
Consider a container with some fluid of density $\rho_l$ and volume $V_l$. This is kept on a measuring device and has weight $\rho_l V_lg$. Now, consider a block of density $\rho_b$ and volume $V_b$. This block is put into the fluid and here, its apparent weight equals $\rho_b V_bg - F_b$ , where $F_b$ equals the buoya... |
The problem related to this post, but my question is even more elementary.
In p 101 of Polchinski's string theory vol I, it is stated
Using the state-operator mapping, the vertex operator for the closed-string tachyon is
$$V_0 = 2g_c \int d^2 \sigma g^{1/2} e^{ik \cdot X} \rightarrow g_c \int d^2 z : e^{i k \cdot X}... |
This is a simple system consisting of a tree of numbers such as ((1 2 (3 4)) (2 6) 1 6) and a rule of application, that states that a tree A applied to B is a copy of A, where every number matching its own deepness on that tree is replaced by a copy of B. For example, that sequence applied to "9" is (1 9 (3 4)) (10 6) ... |
In discussions of the history of our Universe, photon temperature is substituted for time. As the Universe cools, phase transitions break symmetries, including electroweak symmetry.
Why does it make sense to speak of photon temperature prior to Electroweak Symmetry Breaking (EWSB)? Is this a misnomer? Is it shorthand f... |
As you know if I want to find the force for an accelerated object I will use the law $F_o=ma$ so I can get the affecting force of it.
But there is another force affecting against the object. It's the air resistance force, So I will have to calculate the drag force (Air resistance force) and the subtract it from the acc... |
Consider that a large room(an indoor badminton court) is orbiting the earth with a person floating exactly at its center without any relative initial velocity. Consider that the person has no spacesuit(so he can freely breathe, see below.) and the room is pressurized. Can the person reach the edge of the room?
I'm thin... |
This question seems a lot like one of those "Phylosoraptor" memes all over the Internet, and it might be very silly, but I've been thinking about this for a while.
Is it possible that space is not actually expanding but rather, the speed of light is decreasing throughout the entire Universe? ...as if light were traveli... |
In the second edition of Classical dynamics of particles and systems by Jerry B. Marion, it is said that the van der Pol equation
$$\ddot{x}-\mu\left({x_0}^2-x^2\right)\dot{x}+{\omega_0}^2x=0$$
where $\mu$ is a positive parameter of small value, has a limit cycle with amplitude $|x_0|$ (I'm paraphrasing this from the f... |
If I have a system in which I introduce 100e.u.F (energy units) derived from chemical energy (i.e. fuel) and generate thermal energy to heat water what are e.u. absorbed by water? I.e. the efficiency of the transformation?
Basically I would like to know the average/general efficiency of energy transformation for a dis... |
How likely is it in a binary or multi-star system for a non-star celestial body to revolve around the primary star rather than the companion star?
|
When it comes to things like gravity and the electromagnetic force, masses aren't reduced-but with nuclei the mass difference is noticeable. What about nuclear forces makes them capable of putting mass into binding energy?
|
Suppose I have a lab frame that is freely falling in a gravitational field of the Earth -- assume non-homogeneity-- and a uniform constant electric field. There are 2 test particles in the frame -- both of mass $m$, but one is of charge $e$ and the other neutral. They are initially separated by by a vertical distance $... |
I'm really confused about the argument in Cardy's book for why there can't be long range order in 1D for discrete models. Let me just copy it out, and hopefully someone can explain it to me.
He takes an Ising-like system as an example. We start with the ground state with all spins up, and we want to see if this state ... |
Will a person on top of hill will age faster than one at sea level due to Time Dilation?
|
As our homework, we were asked to derive $P = I^2R$.
Now, I started off with the basic relation $P = \frac{W}{T}$. I was not able to think of anything from here, so I started plugging in random formulas from a purely algebraic point of view.
I tried the one for voltage $V = \frac{W}{q} \implies Vq = W$ and got $P = \... |
Ohm's Law tells us that $V = IR$. This implies that $I \propto \frac{1}{R}$. But, $R \propto l$, where l is the length of the conductor. This would mean that $I \propto \frac{1}{l}$. But this does not fit with the definition of current that says that current is the amount of charge $Q$ passing through a given point per... |
I have been reading about Time dilation and twin paradox in Relativity. So,I thought that if It can be the difference of 10 yrs between the Girl in space and on Earth, then why can't anyone not age rather. Is it possible?
[I'm 14 and new in the field of modern physics, so pls correct if I'm wrong. I regard All of You a... |
Continuous symmetry of the action implies a conservation law, but what if equations of motion have a continuous symmetry? Does it imply a conservation law?
Also is symmetry of equations of motion also a symmetry of the action?
I assume that the equations of motion I am talking about follow from the action, i.e. the... |
This is a followup question to this pretty good answer regarding deriving the Boltzmann equation.
What if the center of the target particle is actually not the same with the scattering center (or may not have a scattering center)? For example, see the classical problem of hard-sphere scattering.
|
For example, should we write the dimension of mass, e.g. $\mathrm{kg}$ as $[M]$ or is it enough to write it as $M$?
|
Consider a simple circuit with a battery of $\theta\ \text V$s, and two resistors of $R_1 \ \Omega$s and $R_2\ \Omega$s connected in series. Let us assume that $R_1$ is connected nearer to the positive terminal of the battery. We are required to find the power $P_1$ and $P_2$, dissipated in these resistors.
Now, here ... |
In F. Schwabl, Quantum Mechanics p.148 it is explained that if we have a particle in an electromagnetic field given by potentials $\varphi$ and $\mathbf{A}$ with wave function $\psi$, then a gauge transformation
$$\mathbf{A}'=\mathbf{A} + \nabla\chi\ \ \ \ \ \ \varphi'=\varphi - \frac{1}{c}\frac{\partial\chi}{\partial ... |
According to the wikipedia article http://en.wikipedia.org/wiki/Naked_singularity:
"Some research has suggested that if loop quantum gravity is correct, then naked singularities could exist in nature, implying that the cosmic censorship hypothesis does not hold. Numerical calculations and some other arguments have also... |
Consider the following problem:
There are two spherical conductors $A, B$, with capacitances $C_A, C_B$ resp. Conductor $A$ is supplied some charge and is found to have a potential of $160 \space V$. Conductor $B$ is also supplied some charge and is found to have a potential of $50 \space V$. They are then connected so... |
At what point of a pendulum's swing is its acceleration the greatest? What does this tell you about where the forces act in a pendulum?
Is my answer correct?
The force that causes the acceleration of the pendulum is due to the weight of the pendulum. The weight is constant but if the pendulum is still, hanging in a dir... |
Is it a myth that yelling to a coffee mug will heat it? I have been hearing my friend saying that screaming will heat coffee or water.
|
I have hit a bit of a roadblock in my simulation. In the equation I require the aperture size for the laser source.
$$I_a ≈ \frac{\lambda d}{A}$$
$I_a$ = aperture atop the atmosphere ($m$)
$\lambda$ = wavelength of laser (in this case 1023nm)
$A$ = aperture of the laser transmitter (...? $m$)
$d$ = distance from SPS t... |
There is an experiment we learned from high school that demonstrated how atmosphere pressure worked.
Fill a cup of water and put a cardboard on top of it, then turn it upside-down, the water will not fall out. The explanation said this was because the atmosphere pressure was greater than the water pressure, which holds... |
Consider the following parallel-plate capacitor, with a potential difference of $V$ across it's plates:
I've seen some problems that assume a dielectric with a variable electric permittivity of
$$\epsilon=\epsilon_0\left(1+{z\over a}
\right)$$
or something similar (but a function of z) between the plates.
With these ... |
Consider a isolated system of $n$ non-interacting classical particles. We can easily select a barycentric frame of reference, where total momentum will be zero, so we have our $\vec x(i)$ — coordinates particle $i$ and $\vec v(i)$ — velocity in barycentric frame of reference.
Now I'd like to find a frame of reference w... |
In this article, the author tried to explain that, Einstein's theory may not valid because he says "photon can decay because it may have minute amount of mass". I'm totally in a conundrum state that how to take this article?
Anyone can explain a bit please.
|
I met a problem of derving the Weyl transformation on the closed-string tachyon, Eq. (3.6.8) in Polchinski's string theory, vol 1, p 103.
Given the vertax operator of the closed-string tachyon
$$V_0 = 2g_c \int d^2 \sigma g^{1/2} e^{ik \cdot X} \tag{3.6.1}$$
It is said the Weyl transformation of Eq. (3.6.1) is
$$\... |
I know that having a net angular momentum will contradict isotropy of the universe by preferring a specific direction. But is there any experimental data on the total angular momentum of the universe and how much it deviates from zero (perhaps according to the CM frame)?
|
I have a fairly simple question about a normalisation factor. After normalising a wavefunction for a particle in an infinite square well on an interval $-L/2<x<L/2$ I got a quadratic equation for a normalisation factor $A_0$ which has a solution like this:
$$A_0 = - \frac{8\pi}{6} \pm \sqrt{\frac{8^2\pi^2}{36}+\frac{3... |
I have saw this picture in wikipedia
and I begin to wonder why doesn't current space launches take consideration of avoiding space debris, as say you want to sent a robotic mission to mars, during the launching phase do you have to calculate your trajectory to avoid colliding your spaceship with near earth debris, or ... |
How do we measure a quantum particle properties? (length, mass and time)
|
I am currently trying to calculate apparent positions from raw JPL data.
I've got it pretty much figured out, but there is one thing that's bugging me: Has the light time correction of the moon to be done heliocentric or geocentric?
Light time correction is needed because the speed of light is finite and therefore the ... |
Problem:
A block B of 1,5 kg is attached to the right of a spring (not deformed, with its right side attach to a wall) with a constant of $k = 80 N/m$ and, at rest, the block enter in collision with another identical block A. The block A moves to the left with a velocity of 5 m/s before the collision. Consider successi... |
These papers describe a phenomenon referred to as "atomic collapse" and "supercritical charge" in graphene: Wang et al., Pereira et al.
"Atomic collapse" appears when you have a large enough Coulomb potential in a system described by the Dirac Equation. In the case of graphene, a localized state is embedded in the cont... |
Photons have no mass. Yet they interact gravitationally, as all energy does, with other energetic and massive particles. This means that if you put multiple photons in a system, you get something that appears to have mass, even though none of the constituent particles do have mass.
That makes me wonder:
Is mass really ... |
Although each collision at CERN has the available energy to create a Higgs boson each time, the vast majority of the time it does not create one. I suspect that part of the reason for this is that most of the energy goes into creating mostly lighter, secondary particles which carry a lot of kinetic energy away. As a re... |
I've read several other answers on here, but I still don't understand. Why do both fission and fusion release energy? I know the masses drop, but then why do the masses drop on both? Fusion is taking two small nuclei, adding them together, and creating a bigger atom, why should this bigger atom have less energy? Is it ... |
If we begin with the equation for time dilation:
$$ \Delta t^\prime = \frac{\Delta t}{\sqrt{1-\frac{v^2}{c^2}}} $$
Now, for a particle moving in space with no potential energy,
$$ E = \frac{1}{2} mv^2 $$
So
$$ v^2 = \frac{2E}{m} $$
Then
$$ \Delta t^\prime = \frac{\Delta t}{\sqrt{1-\frac{2E}{mc^2}}} $$
$$ = \frac{\Delta... |
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