All Questions
221
questions
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35
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Massive equivalent of a photon and deduction of a photon's linear momentum
Since photons have an energy given by $E=h\nu$, we could define a particle whose rest mass is such that it has the same energy than the photon: $E=m_0c^2 \Longrightarrow m_0=\frac{h\nu}{c^2}$. We now ...
- 1,616
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3
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150
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Can matter be mass and energy simultaneously? [closed]
I am well aware of the fact that this question is very elementary and I should not have posted it on StackExchange. I wouldn't have had, but most of the reddit forums where I ask questions have gone ...
- 95
5
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2
answers
850
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Does kinetic energy rely on the observer mass too since velocity is relative?
There is no 'correct' inertial reference frame according to relativity. Objects are only 'in motion' relative to an arbitrary inertial reference frame. So let us take the following example. A person ...
- 1,009
-1
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1
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129
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"Information Catastrophe" and measuring density of planets?
In the article https://arxiv.org/pdf/2009.01937.pdf the term "Information catastrophe" is explained. Suppose the later proposed experiment by this author https://aip.scitation.org/doi/10....
- 180
6
votes
3
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181
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Why protons and neutrons don't have less mass than their constituents?
A system of gravitational attracted objects weight less than the sum of their individual masses because it needs energy to move them apart and overcome the gravitational attraction. Same is true for ...
- 793
1
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277
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Is effective mass used in calculating kinetic energy of electron in semiconductor?
Is effective mass used in calculating kinetic energy of electron in semiconductor? I recall it was just used to take into account the internal forces so that expression of force fits well. But why
$...
- 23
3
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2
answers
151
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How does most energy get transfered to mass at high relavistic speeds, but mostly to movement at low speeds?
From what I understand about relativity, it is impossible to accelerate a massive object to the speed of light because it's mass would become infinite. Once an object is moving close to the speed of ...
- 79
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2
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408
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Derivation of Energy-Mass Equivalence: Total energy = kinetic energy $+ mc^2$ [duplicate]
How do you derive the energy mass equivalence just from special relativity? To be exact, in this video, https://www.youtube.com/watch?v=KZ8G4VKoSpQ, at around 23 minutes in, he claims that the total ...
- 480
2
votes
1
answer
43
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Change of velocity without doing work
Body of mass $1\rm\, kg$ is moving towards left side at velocity of $-2\rm\,m/s$ and is slowing down due to the constant external force until it stops. After that, it's speeding up towards the right ...
- 25
1
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3
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205
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Considering $E=mc^2$, what really is a Joule?
A newton is defined as the force able to accelerate a mass of $1kg$ by $1m.s^{-2}$ : $1N=1kg.m.s^{-2}$.
Then, a joule is defined as the work done by a force of $1N$ moving an object by $1m$ : $1J = 1N....
- 193
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85
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Does the intrinsic energy of an object vary, if measured at different heights in a gravity field?
The gravitational redshift has different interpretations. Several quantities vary with height (or seem to), by the same equation - time, energy, mass. I wondered if measurements can shed some light on ...
- 85
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2
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80
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Is there a proven causality that energy-matter causes curvature in spacetime?
I'm not very knowledgable in physics, sorry.
I've read and (somewhat) understood that energy-matter causes space-time to curve but I was wondering about the causality in the statement.
Is this ...
- 3
1
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3
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66
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Besides traveling at the speed of light, how can we be sure that it is possible to have energy and momentum without mass?
How can we be sure that it is possible to have energy and momentum without mass? If something were to continually lose energy, would it not also lose a corresponding amount of mass? I understand that ...
0
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34
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Would it be possible to design a dart-like object such that it survives re-entry and impact at interplanetary / interstellar speeds?
I was wondering about spacecraft - specifically just getting from point A to B. If you were unconcerned about human survival and damage from g-forces, it would be much easier to deliver it without the ...
- 11
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2
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470
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Nuclear fusion kinetic energy nucleons theory
Is this theory correct?
I got this theory from a nuclear fusion expert in stack exchange and he told me to confirm it here...
The theory:
When two nuclei come closer enough (due to external energy ...
