1
vote
1answer
26 views

Wind turbine impact on cars fuel consumption [on hold]

I have question that I still can't resolve. How much cars fuel consumption rises(l/100km) if I attach 1 kW wind generator to cars body? How can I calculate that and what do I need to know? ...
0
votes
2answers
73 views

If there are two conserved quantities that do not commute, why is there typically another?

I have come to the following conjecture: Consider two observables $A,B$ that do not commute and represent conserved quantities, there is typically a third conserved quantity. E.g. for some ...
0
votes
0answers
31 views

Calculating rocket thrust [on hold]

for my recent project I'm trying to compute somewhat accurate rocket physics (although approximations are good enough - for example for aerodynamics). The project is about making "game-like" ...
-3
votes
0answers
24 views

Travel time in combined driving/walking trip [on hold]

A car is sent to take a student from coaching every day. The car arrives at the coaching 15min before the time. One day coaching gets closed one hour before the usual time. Then the student without ...
0
votes
1answer
43 views

Representing Hamiltonian in discrete position basis

I am trying to numerically find eigenstates of an Hamiltonian. Let $V(x)$ be some potential. Suppose my space is between $-L,L$ and that the allowed positions are every $\Delta x$, such that ...
1
vote
0answers
19 views

Adiabatic approximation with scaled time?

In this article (page 3) they have following expression for the coefficients in the adiabatic approximation: $$\dot a_k(t)=-a_k(t) \langle k| \dot k \rangle -\sum_{n\ne k} a_n(t) \frac{\langle ...
0
votes
1answer
28 views

As hot air rises is the cold air that rushes in pushed in or sucked in?

I seem to remember from high school, the state of equilibrium. Volumes of more molecules wanting to get to a volume of less molecules and causing a state of equilibrium. From this I believe cold air ...
1
vote
0answers
19 views

Heating of mixture of gases with one gas barely above its boiling point

What happens when mixture of two gases is heated in a closed container? If one gas expands faster than the other and increases pressure of the container enough so that the boiling point of the other ...
0
votes
1answer
60 views

Critical Value for Dispersion of light [on hold]

If there is a ray of light moving from $n_1$ to $n_2$ you can get dispersion if $n_1$ is a function of wavelength. What angle of incidence ($\theta_1$) will maximise the dispersion? My solution so ...
0
votes
1answer
18 views

The direction of electric field in a thin hollow cylindrical insulating shell

Consider a thin hollow cylindrical insulating shell like the one above draw in 3D-coordinate with Z-axis going out of page and is centered at the origin of XYZ axis. It has electric charge +Q ...
0
votes
0answers
22 views

How to obtain the Klein Gordon equation for DBI action?

The action for DBI field is given by $$S=d^{4}x\,\sqrt{-g}\left[- V(\phi)\sqrt{1-g^{ij}\partial_{i}\phi\partial_{j}\phi}\right]$$ And the required Klein Gordon is given by $$\square ...
0
votes
2answers
20 views

Beam of light from glass to air

I am reviewing some concepts on light and came across a question that puzzled me. A beam of light is incident from a glass into air. The incident ray is 60 degrees to the normal. The question actually ...
0
votes
1answer
15 views

Translational Velocity

Is the translation velocity equivalent to its real velocity or radial velocity? Online sites and textbook are saying different things, So Im not too sure what is going on
7
votes
2answers
240 views

Damped oscillator: time-reversal, time-translation and dissipation

The equation of motion of a damped oscillator $$\frac{d^2x}{dt^2}+\gamma\frac{dx}{dt}+\omega_0^2x=0$$ which is invariant under time-translation $t\rightarrow t+a$, but not under time reversal ...
-4
votes
0answers
21 views

Floating of a dead body [on hold]

Why does a dead body float on water? And why does it float by making head downward? The dead body floats due to the production of gases. But how are the gases produced? And which gases are produced? ...
-1
votes
1answer
36 views

Unification of Newtonian gravity and electrostatic force [on hold]

Can we not unify Newtonian gravity & electrostatic force? All properties are almost same. We can imagine the atoms of the Earth's core to become dipoles when a body is freely-falling. Thus, due to ...
1
vote
0answers
19 views

Can charged scalar have non zero vev?

In Higgs-Kibble mechanism, if we consider a SU[2]_L doublet of complex scalar fields, then one of them is charged and the other neutral. Why does the neutral field acquire vev and not the charged one? ...
-3
votes
0answers
20 views

The state below has non-zero entanglement, but why is its discord zero? [on hold]

|ψ⟩=(|00⟩+|11⟩)/√2. after calculation, I get $\delta=cos^2(\theta)\log cos^2(\theta)+sin^2(\theta)\log sin^2(\theta)$, Its minimum value is 0, therefore the discord of the state is zero. But there is ...
0
votes
0answers
8 views

Relation between phase of dark field and bright field images

I am trying to understand how the super-resolution technique based on Fourier Ptychography 1. In the paper, we run phase retrieval algorithms using images captured using illumination at different ...
0
votes
3answers
31 views

Ohm's law and an ideal voltmeter

In an ideal voltmeter there is infinite resistance so because of which no current is flowing through it and the voltage reading is not affected. The ohm's law stated that V = I * R In an ideal ...
2
votes
1answer
29 views

What does a one-photon state look like as a wave functional?

According to a post on a mailing list here: https://groups.google.com/d/msg/sci.physics.research/n7Ao7N9aeq0/wqgj20-jBQAJ In general, quatum states |Psi> of the electromagnetic field, no matter ...
0
votes
0answers
44 views

Has Rovelli proven that time doesn't exist? [on hold]

Has Rovelli proven that time doesn't exist? See this paper on the Arxiv for a description of his ideas. I am reading some people argue at length, and inauspiciously, that he has. I am entirely ...
0
votes
0answers
15 views

What is the size/mass of largest metal plate that was moved by casimir effect?

I learned about Casimir effect recently. Is it applicable only on very light/thin metal plates( in terms of micro/nano meters) or is the effect large enough to be noticed on mili meters scale? What is ...
0
votes
0answers
14 views

Could science still exist if the nature of events in the universe would be truely random? [on hold]

Most of the science is based on the study of how something behaves in a well defined pattern. Everything follows a rule. Which is the base of all scientific studies. So, in case if there won't be any ...
0
votes
0answers
18 views

Find the Work Done in this system [on hold]

In Inclined plane if friction force = the weight of the object. What is the total work done by this system?
0
votes
0answers
31 views

How do (special) groups such as U(1) and SU(2) do represent the electromagnetic and weak forces? [on hold]

I don't see how groups, such as the circle group somehow representing electromagnetism, represent the fundamental forces. Where is this connection between maths and theoretical physics? Also, as a ...
-4
votes
0answers
24 views

Will this evaporative cooler work? [on hold]

I have just started o doing a thesis which is basically designing for developing countries…..The idea that I have is based on the zeer pot cooler….It is more or less attached to what is basically a ...
0
votes
0answers
11 views

How one can count how many phonon modes is there in the crystal?

I'm reading the review on phonon and Raman scattering in 2D transition metal dichalcogenides (2D TMDCs). At the beginning of Section 2.1 it is said that, since there are two X-M-X units in the ...
-2
votes
0answers
33 views

Is it because of curvature of time that an non-moving object starts to fall down? [on hold]

Are there two extremes in general relativity? One, in which the object is at rest, and starts to fall by time curvature, and one in which light is only influenced by the curvature of space?
0
votes
0answers
19 views

Volume of Air pumped in Isothermal system [on hold]

A manual bicycle tire pump has a cylinder with volume V. When the piston is extended, the valve to the tire closes, and air at atmospheric pressure enters into the cylinder through another valve in ...
-3
votes
1answer
45 views

How is the Earth moving in a elliptical orbit around the Sun? [duplicate]

If gravity is transmitted by a four-dimensional fabric of spacetime and the Sun creates a bend in it ,which causes planets to orbit it , shouldn't the planets move in a circular orbit around the Sun ...
6
votes
1answer
70 views

What is the BG Equation?

About 45 years ago or so I was a Physics department staff computer programmer when I was a physics major undergrad. I worked with a professor doing research on nuclear shell models -- he was ...
0
votes
1answer
39 views

Why are dimensions regarded as square/perpendicular?

Starting from the second dimension, the dimensions are basically represented by a square, cube, tesseract, and so on. I don't know if this is a stupid question or not, but is there an obvious or ...
0
votes
0answers
20 views

Does a cathode ray tube emits electromagnetic waves from a steady DC electron beam?

In cathode ray tube, heated cathode emits stream of electrons but when I wrap a coil around tube a current will be inducted in that coil? after all electron beam is a steady DC current? so no emf?
-5
votes
0answers
8 views

Characteristics of EMF [on hold]

EMF Characteristics of Chemical,Magnetic,friction,Piezoelectric,Photoelectric and Thermocouple also advantages and disadvantages and used for.
0
votes
1answer
34 views

Why is weak hypercharge not a function of the number of up or down quarks?

I'm fairly new to quantum mechanics, and I was looking up some basic information about the weak force and it's interactions. I found this equation of weak hypercharge on Wikipedia and quoted a few ...
0
votes
0answers
13 views

What is $\beta^-n$ decay?

I'm looking on the nndc chart of nuclides and am seeing $\beta^-n$. What is this? http://www.nndc.bnl.gov/chart/reCenter.jsp?z=3&n=6
0
votes
0answers
17 views

finding the plane of cleavage in crystals [on hold]

The crystal can be clear such as diamond or shiny like germanium or metallic like galena or fools gold. I would like to cut some of these cleanly along natural cleavage lines. I would also like to ...
0
votes
0answers
20 views

Is the self-interaction mass of a geon related to the mass gap? [on hold]

I wrote in the question about how type II and III solution have longitudinal components and are related to a geon. This mass has a similarity to the mass gap in gauge theories. In light of the ...
0
votes
0answers
12 views

Query about Ramond-Ramond fluxes associated with a Dp-brane

A paragraph in the string theory book by Ibanez and Uranga (String Theory and Particle Physics by Luis Ibáñez and Angel Uranga) has confused me. According to the book (for a screenshot of the ...
0
votes
1answer
32 views

Fermi-Dirac distribution - holes and electrons

The density of probability of an energy state $E$ being occupied by an electron is $$f(E,T)=\frac{1}{1+e^{\frac{E-E_F}{kT}}}$$ and the density of probability of an energy state being occupied by a ...
0
votes
0answers
23 views

Solving ODE with essential singularity [migrated]

I would like to solve the following linear ODE. $y''(x) -\frac{2}{x} \frac{1-3x^4 +2x^3}{1+3x^4-4x^3} y'(x)+\frac{\omega^2}{(1+3x^4-4x^3)^2} y(x) = 0$ Here $x$ is a dimensionless variable which runs ...
2
votes
2answers
36 views

How can an electron's magnetic moment precess around the direction of an external magnetic field?

I am reading this article: The Nature of the Electron by Don Lincoln in The Physics Teacher, Volume 54 (2016), pg. 203, and I ran across the part where he talks about measuring the magnetic moment of ...
2
votes
1answer
65 views

Will the speed of gravity and the speed of light always be the same?

I have been considering the following though experiment: If the entire sun were to disappear at once, would we feel it first due to the sudden drop in gravity or see it first? The answer I have come ...
0
votes
0answers
22 views

Partial Differentiation without chain rule in Euler Lagrange Equations [duplicate]

The Euler-Lagrange equations for a bob attached to a spring are $$ \frac{\mathrm{d}}{\mathrm{d}t}\frac{\partial L}{\partial v} = \frac{\partial L}{\partial x} $$ But $v$ is a function of $x$. Is it ...
0
votes
0answers
25 views

Derivation of Lagrangian [duplicate]

Actually I am beginning to study Lagrangian and Hamiltonian Mechanics. The book that I am considering directly introduces the Lagrangian L=T-V. Though further on the book , the Euler Lagrange ...
-3
votes
0answers
38 views

Can someone explain me magnetic potential? [duplicate]

I don't understand why we can write the magnetic field as a potential vector A, and what exactly this potential is. Is it just a mathematical thing? And how can it help me calculate the magnetic ...
3
votes
0answers
35 views

How are boundary consitions implemented correctly in time dependent hydrodynamics?

I posted this question more than one year ago and got an answer recently. This answer looks good to me, but indicates that something is wrong in my original approach to the problem. Can someone tell ...
0
votes
1answer
26 views

If we actually conducted a twin paradox experiment using a rocket launched from earth

Does the equivalent acceleration / deceleration required to reach whatever speed then come back and rest in the original frame of reference zero out the time dilation effects for each party? So if we ...
-2
votes
1answer
25 views

Mass and spin relation [on hold]

Wich is the relation between mass and spin? If I have a particle that is formed by the quarks $ud^{*}$, if its spin is $0$, the mass of this particle will be smaller than the mass of the particle ...

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