The special-relativistic relation connecting energy with (rest) 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. Use for all manifestations or consequences of the relation.

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22 views

Is mass relative? [duplicate]

This question has to do with the relativistic mass of an object. I have been reading that as energy increases, so does mass to a much lesser extent, and that this applies to kinetic energy as well. ...
3
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1answer
68 views

Gravitational force between Earth and Sun is decreasing

According to one of the most famous equations in physics, i.e. $E=mc^2$, the mass of the Sun is decreasing as it emits energy. So there must be some kind of disturbance in planetary orbits, and if ...
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0answers
20 views

Are electrons packets of energies made up of strings? [on hold]

I always wondered that if electron was a packet of energy it would hold true for most of the experiments and we won't need to deal with wave particle duality anymore,but then matter came in.what if ...
-4
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0answers
39 views

Do Physical Singularities Exist? Is Mass Infinite at $v=c$? [closed]

Looking at the Minkowski light cone and the STR on the Boundary at $v=c$. STR calculates infinite mass/infinite energy which would burn the universe to a crisp. Aren't we simply saying Undefined; and, ...
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1answer
35 views

Can light change the shape of a black hole?

If light orbits a black hole without ever getting closer or further from it, and the black hole pulls on the light from all directions, does the black hole extend at its equator? Would more light make ...
-3
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0answers
45 views

How to work out a black hole radius if you know its density

How would you work out the size of the Schwarzschild radius knowing the energy density of a black hole?
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1answer
76 views

Why isn't mass still being created in the universe? [closed]

I was watching a lecture by Alan Guth and wished I was in the classroom to be able to ask a question. He explained that the total energy in the universe could be very close to zero since mass and ...
1
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2answers
56 views

Is a puffy object heavier than a contracted object?

From here, I know the spring becomes heavier when potential energy stores in it , how about gravitional potential energy? Is the case similar?consider a puffy object, eg, a gas giant, when it ...
0
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1answer
61 views

If matter cannot be destroyed, does that mean that these particles are created somewhere else after breakdown but in the particles original shape?

In the electron collider, after the breakdown into smaller particles, these particles last for a fraction of a second, and then they disappear. My question is: If matter cannot be destroyed, does ...
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2answers
59 views

Could I make a machine that runs on dirt?

This may sound really stupid, but all matter can be converted into energy. So couldn't it be possible to build like an engine that you'd fill up with dirt and it would run. I understand they're would ...
2
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2answers
68 views

Difference between KE “relativistic” mass and heat mass

I have been told in several answers that the term "relativistic mass" is no longer considered adequate wrt. the mass/energy increase in KE. Yet, I read that 1 Kg of gold's mass ingreases by 10^-14 Kg ...
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4answers
243 views

Does $E=mc^2$ mean that an object with mass $m$ travels at the speed of light in empty space? [closed]

I cannot wrap my head around this (Im new to physics), and this concept is troubling me. I think no, but im not sure why?
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1answer
36 views

Is an extended spring gain mass from potential energy? [duplicate]

Is it true that when a spring is extended, potential energy is stored in spring and result in gain of mass of the spring?
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0answers
34 views

How does the speed of light affect energy? [duplicate]

According to Einstein's theorem E=mc2, energy equals to product of mass and speed of light. How does the speed of light affect energy? If it is so, then why is the specific value for the speed of ...
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2answers
78 views

Does a gluon have mass or not?

I was under the impression that gluons had no mass. Then Wikipedia throws this curveball: "Mass: 0 (theoretical value) < 0.0002 eV/c2 (experimental limit)" Which one should a poor soul go by?! ...
-3
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1answer
48 views

Which one of these energy formulas is correct? [closed]

Which one of the following formulas is correct? What do they mean/represent? How are they used? $E=mc^2$ $E^2=m^2c^4+p^2c^2$ $E=\frac{mc^2}{\sqrt{1-\frac{v^2}{c^2}}}$
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1answer
58 views

Why can´t we call the energy released after the annihilation of a particle and its antiparticle `pure` energy? [closed]

As a particle and its antiparticle annihilate each other a huge amount of energy is released, and no mass is left. This energy always comes in the form of force mediating particles (photons, gluons). ...
-3
votes
3answers
113 views

Composition of energy of electron? [closed]

Mass energy of electron is 0.510 998 9461MeV/ c2 1) Does it include energy of electron due to electric field too? 2) If yes, how much? I am more interested in second part. Links:Here John Rennie ...
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0answers
24 views

Why is it that light bends towards gravity when it has no mass at all? [duplicate]

Why is it that light bends towards gravity when it has no mass at all? Is it because of how gravity behaves as mentioned in general relativity? As far as I know, light cannot escape from black holes, ...
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4answers
2k views

Does a box containing photons have more inertia than an empty box?

A box containing photons gravitates more strongly than an empty box, and thus the equivalence principle dictates that a box containing photons has more inertia than an empty box. The inescapable ...
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votes
1answer
46 views

Can we produce energy from pure substance having considerable mass? [closed]

According to Einstein's formula, $E=mc^2$. Any substance which has mass can be converted into energy or energy is also existing in the form of mass. So I am very much interested to build a machine ...
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1answer
109 views

If E= hv then E= mc2 then h=mc2/v! [closed]

E= pc (1) = hv (2), p= mc (3) From (1) and (2): c= hv/p (4) We put (4) in (3): p=hv/p.m => p2=hvm (5) If we use E=hv in (5) we will get: E= p2/m (6) We use (3) in (6) we will get: E= mc2 From ...
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1answer
50 views

Can a High Enough Temperature Create a Black Hole?

My very basic understanding of GR leads me to think that if a substance has a high enough temperature, it can transform into a black hole without a mass required to create a black hole. The equation ...
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1answer
62 views

Why does two masses with energy attract each other?

I have heard that every mass attract another mass with a force directly proportional to the multiplication of their masses and inversely proportional to the square of distance between them, but newton ...
1
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0answers
72 views

Rainbow Black Hole [closed]

In the photon sphere of a black hole the photons are being trapped in orbit, pulled in and trajectories changed. From a safe distance should we see color from the entire spectrum if light in the ...
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0answers
21 views

Relativistic Mass and Potential Energy

In the chapter 16–4 of the Feynman Lectures, Feynman employs a thought experiment to explain why "if two particles come together and produce potential or any other form of energy; if the pieces are ...
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4answers
2k views

Am I just some energy traveled at light speed? [closed]

I don't understand $E=mc^2$ very well, and here is my question: Does this equation mean masses are just condensed energy? And does this mean that the extra energy an object has when traveling at ...
1
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1answer
57 views

Einsteins theory of relativity and formula of kinetic energy [duplicate]

After seeing both Einstein's theory of relativity ($E=mc^2$) and the formula of kinetic energy (K.E=$\frac{mv^2}{2}$), I noticed that that they are mostly the same, with the only difference that ...
0
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2answers
81 views

Does contracted spring weigh more than stretched one?

(One of examples that potential energy contributes to mass.) Does hot object weigh more than cold one? (One of examples that kinetic energy contributes to mass.) If these are true and justified by ...
0
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0answers
36 views

The derivation of the Mass-Energy(including mechanical energy) equivalence principle [duplicate]

(Not duplication! I couldn't find the answer for the general case, instead of the special case that I've already seen in Youtube I hyperlinked.) I will fully satisfy with not only a mathematically ...
1
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0answers
23 views

The mass-energy equivalence is a principle which can not be derived from anything? [duplicate]

Not duplication) I couldn't find the answer for the general case, instead of the special case that I already seen in Youtube I hyperlinked. I will fully satisfy with not only a mathematically ...
1
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1answer
52 views

The Energy Equation

I've been studying the energy equation in relativistic motion $E= \frac{mc^2}{\sqrt{1-v^2/c^2}}$, which can be expanded as $$E = mc^2 + \frac{1}{2} mv^2\text{ + some other terms.}$$ I'm curious ...
0
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0answers
35 views

Solve question with $E=mc^{2}$ [closed]

In the sun, energy is derived from the fusion of hydrogen into helium via the proton-proton chain. The reaction proceeds as follows: ${}^{1}$H$+{}^{1}$H$\to {}^{2}$H$+e^{+}$ ${}^{2}$H$+{}^{1}$H$\to ...
3
votes
1answer
108 views

Can $E=mc^2$ be derived from the Minkowski spacetime metric? $s^2=x^2+y^2+z^2-(ct)^2$?

Can $E=mc^2$ be derived from the Minkowski spacetime metric? $s^2=x^2+y^2+z^2-(ct)^2$? If so, how? Can the equivalence of mass and energy be derived from the Minkowski spacetime metric? Has someone ...
0
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1answer
67 views

Force, Mass, Motion? $E = mc^2$

Does any object needs force to move? If 'yes', does the matter needs mass to form a force? These questions arises from me because $E = mc^2$ and $F = ma$ does not relate and one does not agrees with ...
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1answer
47 views

Can a massless quark exist?

Is there any possible way to extract all the mass of a quark? Probably under extreme Gs or heat or pressure?
0
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3answers
165 views

Why did Einstein took speed of light unit or constant in his equation of relativity?

We can find that no object can have speed more than light from Einstein's equation of relativity because if anything have speed more than light then we get -ve value within square root. But why did ...
1
vote
1answer
36 views

Mass-energy conversion mechanism in supernovas

Fusion of nuclei inside stars switches from exothermic to endothermic for Iron and elements heavier than Iron. Supernovas not only achieve fusion of transuranides (albeit in trace relative quantities),...
0
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0answers
52 views

Does the analogous saying: “matter is essentially 'condensed' energy” have any merit?

Einstein in his derivation of special relativity came upon the equivalence of energy and matter, and given the right circumstances, the relation can go either way - matter can become energy, and ...
1
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1answer
86 views

Deriving a Schwarzschild radius using relativistic mass

Introduction I have shown below two different approaches to deriving the Schwarzschild radius. I know these are less rigorous than the derivation of the Schwarzschild solution however the $\frac{2GM}...
0
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0answers
39 views

Is there a relation between time dilation and (relativistic) mass increase?

I noticed that what once called relativistic mass increase and now is called energy increase is ruled by the same formula the Lorenz factor of time dilation? The formula is too particular to suggest ...
0
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0answers
33 views

Does vehicle tire mass effect efficiency?

This question has an interesting origin: A tire salesman was recommending tires (aka tyres) for a highly fuel-efficient vehicle. He said the vehicle was light (compared to most production cars), and ...
1
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1answer
44 views

Could the rest mass be somehow considered as a very exotic kind of kinetic energy?

In its rest frame a free system of invariant mass $m$ has energy $E=mc^{2}$. That frame is moving in spacetime with a four-velocity whose magnitude is $c$. Inside my brain something asks: Would ...
2
votes
1answer
66 views

Where did all the photon energy go?

From the wikipedia page on dark energy, in reference to the total mass-energy of the universe: The mass–energy of dark matter and ordinary (baryonic) matter contribute 26.8% and 4.9%, ...
2
votes
2answers
85 views

Does invariant mass depends of temperature? [duplicate]

From special relativity theorie we know that $E = mc^2$. When a system acquires energy, mass becomes greater. That is clear for kinetic energy, because we have a formula that gives m as a function of ...
0
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2answers
54 views

Speed of light and infinite energy [duplicate]

While browsing some physics websites, I saw that to make an object reach the speed of light, it requires infinite energy and talked about its relation with Einstein's famous equation $E=mc²$. However, ...
1
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2answers
63 views

Would this be correct for kinetic energy in special relativity?

In galilean relativity $$p=mv$$ and $$KE=\frac{1}{2}mv^2$$ If I understand it in special relativity the equation for momentum is $$p=\frac{mv}{\sqrt{1-\frac{v^2}{c^2}}}$$ In galilean relativity ...
-5
votes
1answer
61 views

What is the affection of stress tensor of spacetime by the energy/mass density moment of a photon? [closed]

First of all what kind of moment exhibits the photon under its propagation to spacetime continium -quadrupole,dipole or monopole! Please, explain me- why. Do Give some arguements! When it propagetes ...