2
votes
0answers
26 views

How do I transform onto a relativistic rotating frame of reference?

In classical mechanics, the usual formula to translate the evolution of a quantity as seen from an inertial frame of reference to a rotational frame is: $$\frac{d \textbf{A} }{dt} \vert_{Inertial} = ...
-4
votes
2answers
60 views

Proving (instead of discovering) the laws of quantum mechanics

A single toss of a fair coin cannot be predicted. But if we observe a large number of tosses, we can prove mathematically the law that roughly half of them will show up heads. The movements of ...
0
votes
1answer
30 views

How to treat partially polarized light with Jones vectors?

I have to calculate the degree of s-polarization (perpendicular) of a transmitted unpolarised light ray when it goes through a glass plate ($n=1.5$) at Brewster's angle (Brewster's window). ...
0
votes
0answers
29 views

Difficult school decision: last year in school, should I take 2 math courses or 2 physics courses? [on hold]

I know this maybe off topic, but you guys are the best people out there to answer this for me. If you had the choice to choose between option 1) Group theory, and Differential Geometry, versus 2) ...
0
votes
1answer
36 views

How many times does the ISS celebrate New Year each year? [on hold]

My question is, how many times each year do the crew of the ISS have an opportunity to celebrate New Year? Does it vary each year or will it be a fixed number? I tried to work this out for myself ...
0
votes
1answer
33 views

Numerical solution for Friedmann equations

My problem today is to solve the Friedmann equations, for those who aren't familiar with them, here they are (in my specific case): $$ \left ( \frac{\dot{a}}{a^2} \right )^2 = \frac{\rho_1}{a^4} - ...
3
votes
2answers
62 views

What's the true reason behind thermal expansion?

Thermal expansion is a normal concept everyday. There are 2 explanations: 1, thermal expansion result in stress, then result in deformation 2, thermal expansion result in deformation, then result in ...
0
votes
0answers
11 views

How to calculate D0->K+K- decay with QCD factorization?

I am studying the decay of D0->K+K- and I calculated the result of Branching Ratio by Naive QCD and I wrote all the equations for amplitude and branching Ration and Hamiltonian and... for this decay ...
1
vote
1answer
52 views

Could this planetary superalignment happen?

Here's the 'superalignment' I'm referring to: We've all heard the stories about 'mystical planetary alignments' that will increase/decrease the effective surface gravity experienced on Earth (one ...
3
votes
2answers
195 views

When objects fall along geodesic paths of curved space-time, why is there no force acting on them?

On cseligman.com, it is written that So, we see things falling with an acceleration which we call the acceleration of gravity,and thinking that we live in a straight line , uniformly moving or ...
1
vote
2answers
60 views

Is gravity a centripetal force?

In curved space-time, there are curved paths. Since curved paths in our experience require some centripetal force to create them, isn't then gravity a centripetal force?
2
votes
2answers
227 views

If gravitation is due to space-time curvature, how can a body free-fall in a straight line?

According to general relativity, Gravity is due to space-time curvature. Then all paths must be curved. If so, how can there be any straight line motion? The body must follow a curved path. So, there ...
0
votes
0answers
26 views

What are some most advanced theories explaining why same charge repel, opposite charge attract? [duplicate]

It is the holidays with a lot to think about. One of the thing that I couldn't get out of my mind was something I read in Stephen Hawking's "Brief History of Time". In it, he described the repelling ...
0
votes
1answer
18 views

Problem with sound intensity equation in displacement amplitude form

The sound or wave intensity is defined by energy transfer rate with time (power) per unit of area: $$ I = \frac{P}{A} \tag{1} $$ so this equation makes sense since the denominator is the area of the ...
1
vote
0answers
19 views

Physical meaning of RG transformation

When we do RG transformation in Statistical mechanics we eliminate unnecessary degrees of freedom and it leads us to the fixed point. How can I visualize it physically?
-1
votes
1answer
16 views

How can we derive the zero work done by the formula of potential energy [on hold]

**We throw a stone through a vertical direction and its fall done so give me explanation about zero work done by potential energy formula. **
0
votes
0answers
12 views

Does the density of matter increase as we approach the big bang? [duplicate]

I am interested in knowing whether it is clear (undisputed) that the density of matter/energy increases as we approach the time of the big bang? Does this follow from the FLRW metric?
0
votes
1answer
37 views

Loop quantum gravity and string theory [on hold]

I am wondering, with loop quantum gravity theory and string theory. They both are quite substantial in their own right, but What are the pros/cons of each in simple understandable terms?
0
votes
4answers
60 views

Does it matter which blanket I take below and which one above when I cover myself with the two? [on hold]

If I take two different blankets to cover myself, does it matter which one I take below and which one above? Will both the arrangements give me the same comfort or one of them will give me better ...
1
vote
4answers
80 views

Why are we still teaching Newtonian physics if it's “false”? [duplicate]

Why are we teaching an outdated theory when the math in general relativity isn't that hard? I really don't see a reason why we should teach a highly oversimplified theory in our schools. For me, it's ...
0
votes
2answers
95 views

Do objects really move in the direction of the force applied?

According to the second law of motion: Direction of the force is in the direction of change in momentum. Now, I came before a problem. Though an easy one, I was perplexed at a point. A ...
0
votes
0answers
35 views

How to simulate 2 AC electrodes putting into a pool in Maxwell3D (ANSOFT)? [on hold]

I am using Ansoft Maxwell3D to simulate the magnetic field produced by an AC current flowing through a water channel. Suppose i have 2 AC electrodes putting at two ends of a water channel or a pool ...
1
vote
3answers
101 views

Do electrons pop into and out of existence around the nucleus of an atom?

What surrounds the nucleus is the probability wave. But are the electrons constantly popping in and out of existence around the nucleus in the cloud?
0
votes
0answers
17 views

Learning Physics [duplicate]

What's the best way to start learning Physics from home? I haven't touched it since my high school course. I know of Coursera and youtube videos? Are there any other sources that anyone can recommend? ...
0
votes
0answers
7 views

Energy needed for exoergic nuclear reaction

To initiate endoergic nuclear reaction (negative Q Value)minimum energy is supplied which is slightly more than Q value. Then what will be the energy needed for intiating exoergic nuclear reaction ...
0
votes
1answer
39 views

Gravitational… confinement?

This is a followup to Ergil's question "Weak isospin confinement?". According to the Wikipedia article on color confinement: The current theory is that confinement is due to the ...
0
votes
1answer
17 views

Is friction acting for average speed if vehicle passing on a banked road?

Roads are usually banked for the average speed if vehicle passing over them. However, if the speed of a vehicle of a vehicle is somewhat less or more than this the self adjusting static friction ...
0
votes
0answers
33 views

Is there a limit to what we zoom into if it is in fact infinite

I read that recently we were able to view the first atom (hydrogen) under a microscope. This got me thinking about the idea of measurements and zoom lenses. Say hypothetically we were able to build a ...
9
votes
6answers
1k views

What is “special” and what is “general” in Relativity?

Initially I thought in special relativity the velocity was constant, whereas general relativity allowed treatment of accelerated frames as well. But now I have heard that SR is only valid locally?
2
votes
1answer
46 views

What is the energy of a Gaussian wave packet?

Suppose we have a potential barrier situation, that is $V(x)$ is zero everywhere except on the interval $[-a,a]$, where it is equal to some $V_0 > 0$. Introduce some Gaussian shaped wave packet to ...
2
votes
1answer
57 views

The subtle differences between angular momentum and centrifugal force?

I am a mathematician wanting to understand the differences between the concepts of angular momentum and centrifugal force. The following two ideas are clear to me from a physical point of view, but ...
0
votes
1answer
45 views

What does vector space and bra/ket space mean? [on hold]

I wonder What are the similarities and dissimilarities between a vector space and bra/ket space?
0
votes
0answers
30 views

Spivak's Physics for Mathematicians [on hold]

I would like to ask for some details on Spivak's Physics for Mathematicians (Mechanics): is this textbook suitable for a first exposure to physics for a math undergraduate? what knowledge is assumed ...
0
votes
1answer
41 views

Collisions in two dimensions: using relative velocity

I am following this tutorial which reviews some physics on collision resolution. I understand relative velocity, the mathematics is not a problem for me. However, despite my head scratching and ...
3
votes
1answer
29 views

Using infrared temperature sensor to measure water surface temperature

Can I use infrared temperature sensor (such as TS118-3) to measure water surface temperature? I'm afraid some effects such as reflection of infrared waves from water surface and blinking because of ...
2
votes
3answers
51 views

Is wave superposition always equivalent to wave interference?

I'm confused when using these 2 words "wave superposition" and "wave interference" since their definition is very similar. So, are these 2 term the same?
9
votes
2answers
191 views

Are all fermions massless at high temperatures?

According to the standard model, the electroweak symmetry is unbroken at high temperatures, and therefore all gauge bosons are massless then. But since fermions are said to acquire mass by a different ...
3
votes
0answers
51 views

Biot-Savart for current carrying wire

A homework question has made me doubt my understanding of the application of the Biot-Savart law. Question: The magnetic field 43.0 cm away from a long, straight wire carrying current 5.00 A is ...
2
votes
1answer
69 views

What are the relative limitations of the Schrödinger, Pauli, and Dirac Equations?

I know there are significant differences in the nature of the Schrödinger, Pauli, and Dirac equations. Although I know a bit about how each works, I don't understand the relative limitations of each ...
2
votes
1answer
26 views

Modelling ions hitting a grid

I want to model the capture of ions by a negatively charged grid made of some proton conductor material like graphene oxide. Are ions captured as soon as they cross the surface, or do they have some ...
3
votes
1answer
63 views

Does water maintain equal level in connected vessels?

Consider a system as illustrated below: There are two 55 gallon barrels used to store water coming down the gutter. These barrels are connected together on the bottom to maintain equal water level ...
0
votes
0answers
12 views

Calculate the length of propellers needed on an electric motor to lift a mass [on hold]

I purchased an electric motor that is rated for 1.5-3VDC, it produces 11,600 RPM with no load and consumes .3A with no load. It is about an inch in diameter and height but I was wondering how I could ...
0
votes
0answers
33 views

Can we convert light to another spectrum?

Could we convert light from one spectrum to another just like how it does in a radium, using some device? If we could do that to a specific part of the emitted light, probably we could make 3-D ...
1
vote
3answers
33 views

Do infrared lamps provide more heat than incandescent lamps?

Infrared lamps seem to be used in situations where you want to produce heat without producing (as much) light. But incandescent bulbs also produce heat. Why not just use incandescent bulbs? My ...
2
votes
0answers
17 views

What does it mean for a Fresnel lens to have two finite conjugates?

I'm in a situation where I need to reverse engineer a product that my company already manufactures and sells, but it wasdesigned too long ago for anyone to remember. It uses a Fresnel lens with the ...
3
votes
0answers
19 views

References or resource recommendation for the mathematics concerning fission

I am working on a statistical problem that appears similar (in some respects...) to nuclear fission. I am interested in the properties of a system undergoing fission around, or near, delayed ...
1
vote
1answer
24 views

How does diffraction cause maxima and minima on a viewing screen

I have a problem in understanding the diffraction phenomenon. At first, it is described in simple way If a wave encounters a barrier that has an opening of dimensions similar to the wavelength, ...
1
vote
0answers
12 views

Criterion of tangled state by using particular transposition of density matrix

Let's have (for simplicity) two-qubit density matrix $\rho $. If we make the particular transposition only by one qubit, we'll get some other matrix $\tilde \rho $. Then the criterion of the mixed ...
1
vote
3answers
52 views

Space time curvature bends back

If our perception of space-time curvature is gravitation and Reduced Gravity Plane can reach weightlessness on some point of its trajectory, doesn't that mean that when Reduced Gravity plane reaches ...
17
votes
3answers
1k views

I was told that if the Moon had a retrograde orbit, tides would have a faster rhythm. Why is that?

Would this be because tidal deceleration causing the Earth to spin faster or are there other actions in play that I haven't considered? Would the Earth even spin faster because of the tidal ...

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