1
vote
4answers
906 views

How do EM waves propagate?

I have read about this and what I surmise is that when charged particles such as electrons accelerate they produce time-varying electric fields. These E-fields produce H-fields and the process goes ...
1
vote
1answer
143 views

How does enthalpy help us to find the state of equilibrium?

For an adiabatic system with constant external (generalized) forces, in a state out of equilibrium we have: $$\delta H\leq 0 $$ If I understand correctly, derivation of this inequality does not rely ...
-1
votes
0answers
6 views

What is a safe viewing distance for nuclear fireworks?

So people are setting off explosions and bragging about how big they are (fourth of july, you know), and I was wondering about setting off a big one. So lets say that the local firework show wanted to ...
0
votes
0answers
2 views

How does an inductor store magnetic energy?

So I am trying to figure out what the potential energy of an inductor with a current really means. In a capacitor, the energy stored works like this: if you let the plates attract each other, before ...
0
votes
1answer
15 views

Work done in a capacitor with a conductor between its plates

I have been agonizing over this problem, and have tried for more than two hours two find it with Kirchhoff equations, but I end up with 0=0 or some algebraic monstrosity. I have the following ...
0
votes
3answers
72 views

Speed as the fifth dimension

In spacetime there are four general dimensions, three of space and one of time. Why is it that other dimensioned qualities seem to be rarely considered as part of spacetime? For example, why isn't ...
1
vote
3answers
48 views

Why is the definition of mass and matter interlinked?

In my textbook the definition of matter and mass are: Matter: Any thing that occupies space and has mass . Mass: The amount of matter contained in a body. While defining "matter" we refer to ...
-1
votes
0answers
9 views

Is the wobbly rope depiction of a radio wave inherently wrong? And how do vectors of parallel waves align with each other?

I don't have a scientific education, yet I'm scientifically curious. Among other things, I'm struggling to understand the nature of electromagnetic waves. What I have recently realized is that the ...
0
votes
3answers
43 views

How much force does it take to move the Earth?

If you could fly and survive in space, how much force would you need to move Earth at 1 meter per second?
7
votes
3answers
371 views

How does the heat death looks like from inside the system?

As this answer points out, any human would first freeze rather than experience the heat death. However, assuming hypothetically that we could make some robot live at such low temperature (or even ...
0
votes
2answers
407 views

Are there any non dissipative-non conservative forces?

Although the question stands for itself, I would like to know that if the answer has to be no then does any particular law forbids the existence of such forces; and if there are such forces then what ...
-1
votes
1answer
24 views

Thermal contact burn

My client fell asleep in a bus stop leaning back against 3/16 in clear plate glass For an hour with a tee shirt on. It was about 80 degrees Fahrenheit and the sun was shinning on the glass. He woke up ...
0
votes
1answer
44 views

Problem with quantum Hall effect and Berry curvature

I am having trouble proving that the Hall conductivity is equal to the integral over the Berry curvature in momentum space. In the TKNN (1982) paper, using the Kubo formula $$ \sigma_{xy} = \frac{ ...
-2
votes
0answers
12 views

Conseptual Questions on Optics

a man of height h is standing in centre of a room in which a mirror is hanging to the opposite wall the height of the mirror required to see the full height of backside wall in the mirror is
2
votes
1answer
78 views

2D square lattice, nearest neighbor and next-nearest connected by springs

For my field theory class I am trying to build the Lagrangian for the following system. Consider a 2D square lattice where the nearest and next-nearest neighbor interactions are modeled by springs ...
6
votes
4answers
426 views

Do electrostatic fields really obey “action at a distance”?

In an electromagnetic theory class, my professor introduced the concept of "action at a distance in physics". He said that: If two charges are at some very large distance, and if any one of the ...
0
votes
2answers
69 views

Does gravitational field has gravitational mass?

Other questions closely related to the one of the title (as I will show) are Does speak about work done on photon has sense? Does photon has a gravitational mass? Does exists a modern (and more ...
3
votes
1answer
100 views

Observation of gauge in artificial magnetic fields

In the ultracold atom community, an "artificial gauge field" or "artificial magnetic field" is a spatially varying hopping phase somehow engineered into the system, so that atoms hopping around an ...
0
votes
0answers
16 views

Can plasma in a Plasma ball be used as a source of true randomness?

This is just a thought but I've been staring at the Plasma Ball on my desk for a while and after a while I realized the plasma rays/waves/beams seem to be generated in a different spot each time so I ...
3
votes
1answer
188 views

Fluid dynamics tsunami

I have been given a energy head (pressure) in meters for a given tsunami on land. If the tsunami hits a wall 1 meter by 1 meter, is it possible to calculate the height it will reach. I am thinking it ...
-4
votes
0answers
18 views

Is it possible to use electromagnetic waves to power an entire city

I have a theory that it's possible to produce a huge amount of electric current through electromagnetic devices placed in four directions (N.S.E.W) with each facing the opposite side and an amplifier ...
1
vote
2answers
397 views

Determining the neutral axis of an I-shaped cross section with dissimilar materials

Determine the neutral axis of the I- shaped cross section with dissimilar materials. The top rectangle of the cross section is made out of aluminum and the second and third part are titanium ( these ...
3
votes
1answer
103 views

Is the Legendre transformation a unique choice in analytical mechanics?

Consider a Lagrangian $L(q_i, \dot{q_i}, t) = T - V$, for kinetic energy $T$ and generalized potential $V$, on a set of $n$ independent generalized coordinates $\{q_i\}$. Assuming the system is ...
2
votes
1answer
60 views

Is the stress energy tensor continuous at the interface between an object and vacuum?

The stress energy tensor has (as I understand) zero value in the region where there is no matter and non-zero value where there is matter. Suppose there is one matter object in space, now how does the ...
6
votes
5answers
981 views

Is there a depth at which a human body, with lungs full of air, will no longer float?

I was watching a special on divers who dove down hundreds of feet without tanks or gear. The show referred to a depth at which the diver was no longer buoyant and would actually sink, even with lungs ...
0
votes
1answer
183 views

Dielectric sphere placed in another dielectric medium with uniform external field: is there a surface charge density?

Consider a dielectric sphere placed within a dielctric medium. There is a uniform electric field $E_0$ present throughout in the medium. Would there be surface charge on the sphere?
-1
votes
0answers
32 views

What does the universe expand into?

I was wondering that if the Universe was expanding, what was it expanding into. I came up with a theory and I was wondering if there was any information to support my theory, if my theory is wrong ...
1
vote
1answer
38 views

Does the Heisenberg uncertainty principle preclude moving in a straight path with certainty?

The uncertainty principle is σₓσₚ ≥ 0.5 ℏ where x is position and p is momentum. Consider a 2d plane. If one moves along a straight line along the plane (possibly backtracking or moving forwards but ...
-2
votes
2answers
34 views

Doubt on resistor circuit [on hold]

How are we able to flip the triangular resistor to the opposite breaking its connection with the lower 2r resistor?
-3
votes
3answers
79 views

Can pure mathematics alone give proofs in science [on hold]

I reasoned in my last post that because of science's nature of induction and falsifiability, it is impossible to give a theorem in science, unlike in mathematics. It is because even when a scientific ...
1
vote
0answers
34 views

How does the Higgs field relate to the Yang-Mills fields and gauge theories in general?

I asked this in astronomy How does the Higgs field relate to the Yang-Mills fields and gauge theories in general? but they suggested I ask it here. It is very confusing. Is there an easy ...
0
votes
1answer
165 views

Finding the total energy in centre of mass frame

I'm working through a problem in a special relativity textbook (Woodhouse) and I'm having some difficulty. I have to show that if I have a particle of rest mass $M$, total energy $E$ colliding with a ...
1
vote
0answers
22 views

Why didn't we have inflation when the theory of everything and GUTS broke symmetry?

I asked this in astronomy and they suggested I ask it here. Inflation seems to have occurred when the symmetry breaking of the electroweak occurred. But do we know of any reason why we did not have ...
2
votes
1answer
223 views

Hookes law and objective stress rates

Often, in papers presenting updated Lagrangian simulation methods for solid dynamics, the following procedure for updating the (Cauchy) stress tensor is presented: First, the Cauchy stress tensor is ...
-2
votes
0answers
62 views

Understanding sine waveform [on hold]

I want to study the basics of propagating a periodic signal, i.e. sine waveform, which is a power signal. Let us consider an alternating current and write its expression as $$I(t) = I_m \sin(2\pi f ...
0
votes
1answer
27 views

Wavelength of light too long to measure electron position in double-slit experiment?

I'm a mathematician, so I am not familiar with experimental physics. I am watching MIT course on Quantum Mechanics, and they describe the two-slit experiment with electrons passing through the slits. ...
0
votes
2answers
103 views

Projectile, air resistance and wind

So for my school project I am working on a projectile simulator and air resistance. So I have looked at this. Equations for an object moving linearly but with air resistance taken into account? ...
0
votes
1answer
81 views

Why is wave energy zero at maximum deviation?

The equation for the energy density of a longitudinal wave in a thin rod is $$w = \rho\cdot \left(\frac{\partial \xi}{\partial t}\right)^2$$ So the energy density seems to be 0 when the deviation ...
0
votes
2answers
29 views

How does a Venturi Injector comply with energy conservation?

How does a Venturi Injector comply with energy conservation? When the water flow enters the narrower cross section its velocity increases and its pressure decreases. When the pressure gets lower ...
4
votes
2answers
720 views

The uncertainty principle and black holes

What are the consequences of applying the uncertainty principle to black holes? Does the uncertainty principle need to be modified in the context of a black hole and if so what are the implications ...
1
vote
1answer
204 views

Atomic nearest neighbor notation

I recently got a correction to a paper that I am writing. The correction references a section in which I talk about nearest neighbors. The comment says: Do you mean NN, NNN, etc., or NN, 2NN, 3NN? ...
0
votes
0answers
28 views

What am I missing in this reasoning?

In studying the problem of locomotion at low Reynolds number, one possible approach is based on gauge theories. In simple terms, one considers a sequence of shapes of a certain deformable body, say ...
1
vote
2answers
40 views

Radiation from home heaters

My understanding of radiation is energy being emitted from a source. So much radiation would come out of a home gas or oil heater to become dangerous. I'm assuming infrared radiation.
4
votes
5answers
863 views

Can we know if “all” physical laws are discovered?

Before Einstein, scientists believed that all physical laws to be discovered were already discovered. Of course, that was proven wrong. If we somehow manage to come up with the Theory Of Everything ...
0
votes
3answers
73 views

The relation between mass and speed

Massless particles (or luxons) have no (rest) mass ($m = 0$) and a speed equal to the speed of light ($v = c$). Massive particles (or bradyons) have mass ($m > 0$) and a speed lower than the speed ...
0
votes
1answer
77 views

Conversion of energy to matter or antimatter?

We all know that matter converts into energy, but will energy convert into matter? Does it form antimatter by converting? Illustrate me with example.
0
votes
2answers
143 views

Origin of Universe

The universe is believed to have originated from absolutely nothing, and we know it is still expanding. Physics says "something can arise from nothing". I understand how mass and energy are related ...
3
votes
1answer
165 views

Is there any physically relevant example of constructing series solution about infinity of an ordinary differential equation?

I was reading about how to test if a given second order ordinary differential equation has singularity at infinity from Arfken and Weber. I understood the steps mathematically but I could not find its ...
4
votes
2answers
115 views

Simple Harmonic Motion in Special Relativity

I was trying to see what results I would get if I were to incorporate relativistic corrections into the case of a harmonic oscillator in one dimension. I thought that if the maximum velocity of the ...
0
votes
0answers
49 views

Spin 1/2 particle in rotating magnetic field

So, I'm attempting a solution to the following problem: I am given a particle with spin 1/2 in a constant vertical magnetic field and a rotating field in the (x,y) plane. $$B(t) = [B_1\cos(\omega ...

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