0
votes
0answers
26 views

Combining Moment of Inertia Tensors

In a physics simulation of rigid bodies, if I have a cube with a known mass and moment of inertia tensor, and I attach it to another cube with a known mass and moment of inertia tensor such that its ...
0
votes
0answers
20 views

Examples of systems with linear response behavior

I've checking the linear response theory and there are 3 fundamental assumptions. 1) Linearity of the response of the system to an external excitation, 2) Stationary response function: ...
0
votes
2answers
43 views

What unit would the answer be in?

So I have used this formula: $$W= PV_1 \times \ln\frac{V_2}{V_1}$$ and I have converted my values to cubic meters and pascals. So Work Done, $W$, what would be the unit for that answer? I already ...
0
votes
3answers
41 views

Conceptualization and modelling of spin

I'm trying to get a decent understanding of the bell inequality, and so am trying to understand spin both conceptually and mathematically. When I picture spin, I imagine a sphere rotating about its ...
0
votes
0answers
32 views

Maxwell's Equations for Accelerated Conductors

I asked a question about accelerated conductors in a magnetic field but nobody unfortunately answered. That is: Ohm's Law for Accelerated Conductors Maybe, I could not state my question well. I ...
0
votes
1answer
38 views

the twin paradox [on hold]

about einstein twin paradox i don't understand how time will pass differently to one of the twins,it might feel differently but if i traveled to another country and got back in 2hours i might feel ...
3
votes
2answers
85 views

Are Mathematics the language of the universe? [on hold]

I am a high school student and next year i am going to be a physics major, so this year i put all my effort on physics and mathematics, since it a great tool for physicists. But now i wonder, in ...
0
votes
1answer
25 views

What would Negative Energy act like? [duplicate]

So I heard that if you want to make a wormhole you need negative energy. What is special about Negative Energy that allows it to do that? What are the properties of Negative Energy compared to normal ...
0
votes
1answer
22 views

Scale factor and energy density

I'm looking at some solutions of the Friedmann equation at this website: Solutions to Friedmann equation If I look at the first problem (Problem 1: matter or radiation in a flat Universe) and click ...
0
votes
0answers
33 views

Radially free falling observer [on hold]

I am a student. i read in a paper for a radially free falling observer in a Schwarzschild metric, the relation between the Unruh vacuum state and the proper time when the observer crosses the event ...
1
vote
1answer
30 views

Physical Meaning Of $ dQ/T $ Regarding Clausius Inequality: Is it related to Energy Loss in form of heat or Something Else?

What is the physical meaning of term $ dQ/T $ in Clausius Inequality $ dQ/T \le dS $ ? Physically we can relate entropy to number of microstates of a system, which relates to number of possible ...
3
votes
2answers
37 views

Why does a cooling car engine crackle?

Why does a cooling car engine crackle? What determines the frequency of the crackles?
-1
votes
0answers
64 views

Can you debunk this “Perpetual” (ie, very long term) motion machine? [on hold]

In the following design, gravity is "always" pulling down. There's a parallelogram-shaped box containing a magnet, and underneath the lowest corner of the box is another magnet to repel the first ...
1
vote
2answers
55 views

Point-like nature of particle interaction and wave function non-locality

Let us consider the Hamiltonian for the hydrogen atom $$ ...
-2
votes
0answers
20 views

How to write Laplace equation for this problem? [on hold]

How to write Laplace equation in below example. we have two plate with surface S,If we have charge surface density in boundary,obtain potential between two plate. explicitly explain for me how to ...
0
votes
2answers
45 views

If a photon is exists in 'timeless' state, how can objects around it move? [duplicate]

My understanding is that light does not experience time. In attempting to understand what the universe would be like from the perspective of a photon, the answer I get is that the universe would be ...
2
votes
3answers
94 views

Interpretation of systems in different state of matters BUT almost identical configuration

For a start, let me clarify that by "almost identical configuration" I mean same volume, temperature and number of molecules (but different pressure). One could for instance take two identical systems ...
0
votes
1answer
11 views

What is harmonic and fundamental bands in IR spectroscopy?

What is harmonic and fundamental bands in IR spectroscopy? I'm trying to find exact definitions. I guess that fundamental is $1\leftarrow 0$ transition (the most intense and energetic) and harmonic ...
0
votes
0answers
15 views

Postion of a cylinder rolling down an inclined plane [on hold]

I know that the acceleration of a uniform cylinder of known mass rolling down an inclined plane WITHOUT slipping with an inclination of $\theta$ is: $\frac23 g \sin\theta$. Suppose this term is called ...
0
votes
0answers
38 views

Green function integration problem [on hold]

When I'm trying to find the Green Function of Helmholtz equation for a cube $0≤x,y,z≤L$ $$\nabla^2u+k^2u=\delta(\vec{x}-\vec{x}')$$ where $u=0$ on the surface. I set to find the green function where ...
0
votes
0answers
15 views

States in valence and conduction band

I often see a Hamiltonian in second quantization written for the valence and conduction band. Now, I was wondering: What are the single-electron states that form the prouct state they act on? So what ...
1
vote
0answers
39 views

What makes Lattice Yang-Mills hard?

I've been reading up on non-perturbative Yang-Mills, and have found the following equation: $$Z[\gamma, g^2, G]=\int \! \prod e^{-S}\mathrm{d}U_i$$ Now I don't know much about computational physics, ...
3
votes
1answer
52 views

A true singularity at $t=0$, coordinate independent Big Bang

Consider a flat Robertson-Walker metric. When we say that there is a singularity at $t=0$, clearly it is a coordinate dependent statement. So it is a "candidate" singularity. In principle there is ...
0
votes
1answer
15 views

What concepts/rules apply for multi-stage pumping of water

For single stage (ie one pump) water transfers calculations for pressure loss are commonly done by adding the elevation difference of the start and end of the pipe line to the friction losses that ...
1
vote
1answer
27 views

Finding the potential between two spherical shells [on hold]

How to find the potential in region $a<r<b$ I know that the general solution for Laplace's equation is $$V(r,\theta)=\sum_{l=0} \left[A_l r^l +\frac{B_l}{r^{l+1}} \right]P_l(\cos{\theta}).$$ ...
0
votes
0answers
12 views

Excitation probability given pulse bandwidth and atom linewidth

Consider photon source producing photon pulses with a frequency distribution $f(\omega)$ and a glass tube filled with a gas. The atoms of the gas can be excited by photons with a frequency of ...
0
votes
0answers
21 views

Capillary action height

How to calculate height of the liquid (let's say it's water) in the capillary (so height of capillary action) if you only have r given, r = 0.3 mm - r is radius of capillary. The equation I would use ...
0
votes
0answers
18 views

Equal volumetric rate versus area open to flow [on hold]

A vertical water disposal well has been drilled and cased. There are two horizontal rock formations that the wellbore intersects and these formations will be targeted for water disposal. To allow ...
1
vote
0answers
10 views

Evaluation of the anomalous dimensions of fields in SUSY $SU(5)$

The general formula for the anomalous dimension can be found in Martin΄s review article (hep-ph/9709356v6), on page 62 relation (6.5.4). In the case of $SU(5)$ and especially in the paper of ...
1
vote
1answer
95 views

Visualisation of electron

first things first, I'm not by any means a physicist nor a student of physics. I study graphic design. Theme of my bachelor thesis is visualisation of physical and mathematical phenomenons, long story ...
0
votes
1answer
27 views

Reg position of satellite

Is it possible to put an artificial satellite into an orbit in such a way that it will always remain direct over a city (I mean at any specific place)?
6
votes
0answers
33 views

What is the largest number of bosons placed in a BEC?

What is the record for the largest number of bosons placed in a Bose-Einstein condensate? What are the prospects for how high this might get in the future? EDIT: These guys reported 20 million ...
2
votes
0answers
27 views

Why do NNLC and NIST appear to give different values for the mass energy of the deuteron?

There is a problem with data that I've obtained over the internet. Here are the two sources of information from which I'm retrieving my data. NNLC and NIST On NIST, I have read that the mass excess ...
0
votes
0answers
46 views

Good introduction to classical mechanics with math [duplicate]

Right now, I'm reading "Classical Mechanics" by Kibble and Berkshire. Already in chapter 2, I have found a concept being discussed that assumes you have prior knowledge. Specifically, it describes the ...
1
vote
1answer
20 views

Why are unilateral Laplace transforms suitable for causal systems and bilateral aren't?

https://en.wikipedia.org/wiki/Two-sided_Laplace_transform#Causality The above section says that bilateral transforms will not necessarily make sense for causal systems. In the course of advanced ...
0
votes
2answers
66 views

A model that unifies the strong, EM, weak and gravity forces?

Does there exist such a model that explains the force clusters (their origin, relations between them): the strong, EM, weak and gravity forces?
2
votes
3answers
77 views

Is it possible to express various nonlinear motions as straight lines in transformed spacetime?

I am trying to understand simple examples of space-time curvature. Assume for the moment that $c$ is infinite (classical curvature due to Newton's laws). Also, I will only consider 1+1-dimensional ...
1
vote
0answers
45 views

Does the magnification equation help you determine the type of eyeglass lenses? [on hold]

While picking up a pair of eye glasses dropped by a friend, you notice that they form an inverted image of the background and that the image is stretched horizontally as well. Your friend suffers ...
0
votes
1answer
31 views

Condition for formation of interference pattern

I recently came across this in a textbook of mine while studying the Young's double slit experiment. It says a condition for the formation of interference pattern is s/S < lambda/d Where s is ...
0
votes
2answers
35 views

Current lagging voltage by more then 90 degrees

According to Wikipedia https://en.wikipedia.org/wiki/Leading_and_lagging_current An alternating current that reaches its maximum up to 90° behind the voltage producing it is said to be lagging. and ...
0
votes
1answer
30 views

Comparing voltages of Parallel and Series circuits

There are two electric circuits. Resistor 1 ($R_1$) connected with resistor 2 ($R_2$) by series circuit $R_1$ connected with $R_2$ in parallel Each of the circuit has battery with emf and the ...
1
vote
2answers
88 views

How do two electrical charged particles know to repel or attract each other?

Now per QED, electrical charges interactions are effected by photons. Suppose you are one of the two charges. How do you know to attract or repel the other charge? In other words, how do you know if ...
3
votes
2answers
44 views

Viscosity and surface tension

Both viscosity and surface tension are dependent on the intermolecular forces between the molecules of the liquid. Supposing from this, shouldn't there be a directly proportional relationship between ...
0
votes
0answers
35 views

Inverse of a 3x3 matrix! I need some help! [migrated]

I have this 3x3 matrix $$E_{ij} = g_{ij} + \bar{\epsilon}_{ijk}z^k$$ and want to derive its inverse. I know that its inverse is given by $$(E^{-1})^{ij} = \frac{1}{1+z^2}(g^{ij} + z^{ij} - ...
0
votes
2answers
68 views

On which basis we think there is something more than just super dense matter in black holes?

Apparently physicists think that there is something inside black holes. Like a new universe or a link between dimension... But for me a black hole is no more than supermassive supercompacted matter. ...
0
votes
1answer
52 views

Will this sail-based moving system work? Why? [duplicate]

So simple: Will this sail-based moving system work? Why?
-1
votes
2answers
121 views

Is there a binary black hole system in the middle of the galaxy?

We have observed gravity effects from black holes in the center of galaxies, but galactic centers are dusty so we can’t tell if it’s one black hole or two black holes in a binary system in there. A ...
2
votes
1answer
46 views

Spontaneous symmetry breaking of SHO

Spontaneous symmetry breaking refers to the solution of a system loses some symmetry in its Lagrangian. Consider a Simple Harmonic Oscillator, its lagrangian is time translationally invariant but its ...
0
votes
2answers
80 views

Question of Conservation of Momentum

I think I understand the concept of conservation of momentum in an inelastic collision. However, what if two objects, one being more massive than the other, started out together and then separated ...
0
votes
1answer
10 views

What are the Correlations for the Super-compressability Z factor?

I am studying the course TPG4145 Reservoir fluids in NTNU and specifically the supercompressability factor $Z=\frac{V_{\text{real volume of the system}}}{V_{\text{ideal volume of the system}}}$ for ...

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