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Questions tagged [mass-energy]

The special-relativistic relation connecting energy with mass, $ E^2 - (m c^2)^2= (pc)^2 $. May be used to provide accounting constraints in energy and momentum, both conserved in total, even in reactions where $m$ is not.

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The energy mass equivalence relation

I wanted to know that what is the reason we believe that the energy mass equivalence relation i.e. E = mc^2 is true? What experiments other than that on the nucleons, compels us to believe this is ...
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3answers
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Thermal energy turning into mass?

When you heat an object it's mass increases $E=mc^2$. What I don't understand is that this energy can be converted to mass and still be thermal energy too (object still hot). When a radioactive ...
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0answers
30 views

Entanglement and mass-energy [on hold]

Consider two systems of particles. They are identical systems except in one respect: In system A the particles are all entangled with one another, and in system B none of them are. Do A,B possess the ...
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1answer
87 views

Energy-momentum relation in SR and GR

There is the famous energy-momentum relation $$E^2 - p^2 c^2 = m^2 c^4.$$ I thought it is always valid. "Always" means it is valid in general, so in GR and SR. It is something like an elemantary ...
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Local mass function in spherically symmetric spacetime

I am studying the paper `Inflation and de Sitter Thermodynamics' at https://arxiv.org/abs/hep-th/0212327 . I have problems with the way they define a local mass function in a general spherically ...
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2answers
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Do variations of the Earth's magnetic field affect gravitational acceleration at Earth's surface, and if yes, by how much?

The Earth's magnetic field varies with time over geological time scales (we have phenomena such as pole inversion). Can this affect the acceleration of gravity at Earth's surface? I would think that ...
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1answer
57 views

Energy and mass at absolute zero temperature

Hi my question is if the temperature of a particle is reduced to absolute zero the that particle has lost its energy so it has no movement. Particles have mass and Einstein said mass equates to energy....
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3answers
202 views

Does the gravitational field possess an inertial mass? [duplicate]

I understand that inertial mass, at least in part, comes from the inertia of energy in the zero momentum frame or rest frame of some physical system. So for a static charge the corresponding field ...
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2answers
35 views

Mass and Energy conversion in photon

If energy can be converted into mass then why isn't photon's energy being converted into mass?
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11answers
12k views

Why do fusion and fission both release energy?

I only have high school physics knowledge, but here is my understanding: Fusion: 2 atoms come together to form a new atom. This process releases the energy keeping them apart, and is very energetic. ...
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3answers
102 views

Is $E=mc^2$ only partially true? [duplicate]

I've obviously seen that $E=mc^2$. But I've also seen that the equation $E^2=(mc^2)^2+(pc)^2$ (where $p$ = momentum) is true. If you square $E=mc^2$, and subtract the result from the other equation, ...
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3answers
102 views

Rest mass of the photon [closed]

Why is the rest mass of the photon is taken to be zero? If rest mass of the photon is non zero, then it leads to infinite energy of the photon (by $E=mc^2$ equation) and there is a violation of ...
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1answer
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Can we differentiate Einstein mass-energy relation $E=mc^2$ with respect to position $x$ to get force?

The question is as the title. Can we differentiate Einstein mass-energy relation $E=mc^2$ with respect to position $x$ to get force? I don't know whether my question is valid and logical but just ...
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1answer
58 views

When we burn a match stick it did not go at $c$ speed, why?

When we burn a match stick then mass is converting into energy then according to the relativity match stick particles should go at speed of light but it did not happen why
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1answer
20 views

Mass and energy in special relativity [conservation of energy problem] [closed]

A certain quantity of ice at $0$ celsius melts into water at $0$ celsius and in doing so gains $1.00$ kg of mass. What was its initial mass? Now the problem with my solution is that it of course ...
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1answer
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Is this equation for mass defect correct? [duplicate]

I just want to know if this equation for the mass defect is correct $$\Delta m = Z * m_p + Z * m_e + N* m_n - A $$ where Z- Atomic number A- Mass number N- number of neutrons $m_p$- mass of the ...
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2answers
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Electrons Getting mass from energy

According to relation $E=mc^2$ energy and mass are equivalent. So, when an electron in its orbit gets energy from out, does its mass increase? If not, where is the energy stored? I am not ...
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1answer
45 views

Schwarzschild geometry for negative masses

Imagine that in a part of our universe there exists negative masses $M=-|M|<0$. The metric around this object -- say a black hole -- will be of the form $$ ds^2 = -\Big(1+\frac{2|M|}{r}\Big)dt^2 + ...
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2answers
121 views

What gives mass to black hole?

I like to know when a dying star collapsed into a black hole, is there anything inside or on the event horizon that is interacting with higgs field?
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0answers
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Calculate weight of a barbell via measurement of period of oscillations

I have seen some videos on YouTube about some people that use "fake weights" in the gym, declaring to be able to lift much more weight than what is actually on the barbell. However, I think it should ...
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1answer
94 views

Do we know what causes the release of energy in nuclear fission?

I was trying to put together all the things I've read in the last couple of days and I realized that based on my current knowledge of the standard model and the way nuclear fission works, I'm not able ...
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1answer
58 views

Do mass and motion affect space-time differently?

Mass is said to create curvatures in space-time thereby creating gravity, yet technically the smallest movements, even on Earth, create gravitational waves. Are there different "types" of disturbances ...
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1answer
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General proof of $m^2 = E^2 - p^2$

All proofs I know of, starting from Einstein's famous 1905 article, only deal with special cases (actually, yes, I know that formula like $E=mc^2$ were known before Einstein in the context of ...
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4answers
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$E=mc^2$: Why does the speed of light constant affect the Energy or Mass of an object? [closed]

So this is really just for fun. I often talk to my friend who studied some Physics degree (or similar) and he simply cannot accept the possibility it could be wrong in any way. To the point where he ...
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2answers
78 views

Perpetual motion using mass defect

First off, I know this wouldn't work due to it breaking thermodynamics and that there would also be heaps of energy dissipated to the surroundings, and fusion doesn't work yet, but I'm more interested ...
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2answers
48 views

Relativistic Mass when Viewed from Different Frames of Reference

I understand relativistic mass and the equations underpinning it. My question deals with how to calculate relativistic mass when an object is viewed from different frames of reference. Consider a ...
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2answers
2k views

Does converting rest mass to energy instantly change the gravitational attraction it exerts?

Let there be two hydrogen atoms having 1.1 mass each. We use solar fusion to convert the two hydrogen plasma to helium with a mass of 2 and 0.2 gamma radiation. Before the fusion process gravity was ...
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3answers
60 views

How are these two definitions of energy related/derive from each other? [closed]

How are these two definitions of energy related/derive from each other: $$E = \frac{mc^2} {\sqrt{(1 - v^2/c^2)}}$$ vs. $$E = \sqrt{m^2c^4 + p^2c^2}~?$$ Both equations express the relation between ...
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2answers
206 views

Does the inertia of an object changes with its temperature? [closed]

$F=ma$ is not accurate enough at relativistic speeds. Does the inertia of a rigid body related to its temperature?
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3answers
56 views

What is meant in mass' definition 'resistance to acceleration'? [closed]

Wikipedia: Mass is both a property of a physical body and a measure of its resistance to acceleration What does this mean? I know of the $E=mc^2$ formula. I think, the energy required to '...
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information theory and energy mass relationship (E=mc2) - just a hunch … [closed]

I was walking on the street the other day and thought to myself, maybe E=mc2 can be derived from information theoretic principles. I did not do too much work on this, just want to brainstorm a bit. ...
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1answer
80 views

Does a non-spherical black hole have distribution of mass like an empty body, solid body or pointed object?

Suppose a non-spherical (say, rotating or under distortion of another gravity source) black hole. Does it have its mass distributed as if all the mass was on its surface, or as if the mass were ...
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2answers
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What is more massive, Proton, standard Hydrogen?

If you consider the classical states of hydrogen, one in which the electron is rotating at an orbital distance of $r$ and then take $\lim_{r\to\infty}$ one obtains that the $r_\infty$ state has more ...
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2answers
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Is mass-energy conversion contradicting energy conservation? [duplicate]

If mass can be transformed into energy, and energy transformed back into mass, isn't this at odds with the law of conservation of energy? Because this would mean, that in theory, it would be possible ...
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3answers
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Is the relativistic increase in (relativistic) mass same for a freely falling body as compared to body which is accelerated to the same velocity?

For a similar mass either falling toward a black hole or accelerated by a force is there a comparable increase in mass for similar velocity? Suppose a mass of one kilogram is accelerated to 99% of the ...
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2answers
95 views

How does inertia work at the particle level?

I've read recently that the mass of a proton is mostly not given by the Higgs mechanism. But rather it's given by the energy of quarks moving around inside the proton and gluons and other internal ...
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How can the quanta of electromagnetism be photons if they have no mass? [closed]

I thought charge only existed when mass was present. Does this mean String Theory hypothesizes photons having charge?
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3answers
138 views

Why is $E=mc^2$ and not $E=m\frac{c^2}{2}$?

Kinetic energy for a moving object is the integral of force with respect to distance, often given as: $$E=m\frac{v^2}{2}.$$ This would imply that for mass moving at the speed of light, the kinetic ...
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1answer
77 views

Does relativistic mass really increase with velocity? [closed]

Suppose there are two masses on the ground $M$ and $m$. The distance is $d$. So according to newton's law the gravitational force between them is $F=\frac{GMm}{d^2}$. Now suppose that I am going ...
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4answers
184 views

Why does the warm air rises up?

Warm air has more energy than cold air. This means that according to the Einstein equation $E = mc^2$ the warmer air has a greater mass than the cold one. Why is the warm air rising, if it has a ...
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1answer
61 views

When a particle keeps “accelerating” near the speed of light, is the energy gained expressed in linearly gained impulse, or relativistic mass? [duplicate]

When a particle keeps "accelerating" near the speed of light, is the energy gained expressed in linearly gained impulse, or relativistic mass?
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5answers
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What stops a free electron from 'using' part of its own mass to generate radiation?

The explanation I've read on why a free electron can't emit a photon goes like this: Let there be a free electron of mass $m$ moving with constant velocity $v$. We may enter a new reference frame ...
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1answer
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Newton's 2nd law of motion and mass-energy equation [closed]

According to the mass-energy equation $E=mc^2$, so $m=\frac{E}{c^2}$, but according to Newton 2nd law of motion $F=ma$, so $m=\frac{F}{a}$. Therefore $\frac{E}{c^2}=\frac{F}{a}$, or $E=\frac{Fc^2}{a}$....
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2answers
60 views

Binding Energy and Energy Mass Equivalence

Consider a neutral atom. An external force acts on one of its valence electron so that it brings this valence electron to infinity away from the rest of the atom. The electron's kinetic energy does ...
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1answer
84 views

Are particles an abstraction of energy, or their matters do indeed exist?

I'm trying to understand from where the first particles in quantum mechanics came from, and while doing research I got this information from an article about the origin of matter: In the beginning,...
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2answers
63 views

Do the inertial mass and gravitational mass of an object depend on the frame of reference?

My understanding is that the "relativistic mass" of an object means any of the following three quantities (which are all identical): The "mass-energy", as defined by the formula $m = E / c^2$. The ...
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2answers
134 views

What happens if we exert more force on an object which would be travelling at near maximum light speed? [duplicate]

If we exert force on an object which would be travelling at near light speed, to an extent to make it move greater than speed of light in vacuum, what would happen? If object doesn't move faster than ...
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2answers
73 views

How does matter turn to energy at the atomic level? [duplicate]

When matter is converted to energy by means of $E=mc^2$, it produces quite a lot of "energy". What I am having trouble understanding is exactly how the matter is transformed to energy at the atomic ...
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3answers
794 views

Mass-energy in relativity

If an object's mass, when measured in its frame of reference (even if that frame is moving), is invariant, then why does it require more and more energy to accelerate it? I can understand this when ...