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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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What is possible intuitive explanation of inelastic relativistic collsion?

In classical mechanics, we say an inelastic collision happens when some energy is transferred to heat and noise without changing the total sum of momentum. However, in special relativity, every ...
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66 views

Wave and relativity

From Wikipedia, "In physics, a wave is a disturbance that transfers energy through matter or space, with little or no associated mass transport." But Einstein said that energy equals mass so if a wave ...
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Are the units of energy the same in higher dimensions?

In 3 spatial dimensions, $$[E] = [ML^2 T^{-2}]$$ Would it change in higher dimensions? If yes, then what would be the dimensions for 4 spatial dimensions?
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How is a photon converted into matter?

Photon is a mass less particle but still it can be converted into matter which has mass. I know the formula $E=mc^2$, but is there some kind of force or particle which converts photons into matter, ...
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Does infinite mass exist? [closed]

So when I search up if infinite mass exists, google provides me with a source that states infinite relativistic mass does exist at the speed of light which is why it is impossible to ever reach to ...
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1answer
73 views

Useful Momentum Relation for Relativistic Particles [closed]

I've seen that $$p = \sqrt{(\frac{E}{c})^2-(mc)^2} = \frac{1}{c} \sqrt{{E_k}^2 + 2 E_0 E_k}$$ for a relativistic particle on hyperphysics and in my modern physics class. I understand that the first ...
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Are matter and energy dependent on each other? [closed]

If matter creates energy and energy creates matter can one exist without the other?
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91 views

Energy vs. mass in photons

I am confused about the following: Mass is condensed energy. A photon has no mass, but it has a degree (of quantised) energy. Does that mean it does not have enough energy for it to be condensed ...
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The relation between mass, inertia and energy

I have trouble understanding the following concept: I learnt that mass is a measure of inertia, and that seemed logical enough. Yet separately I learnt that mass is a form of condensed energy. If ...
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2answers
83 views

Distortion of space and time

What will happen to the distorted space and time around a mass when it is converted into energy? Will it back to its original configuration (0 gravity)? Or space time oscillates? Or anything else
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2answers
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The speed of light and the increase of relativistic mass [duplicate]

The speed of light theory predicts that as things travel faster their mass increases, so I think we if we look at a plane accelerating from mach one to mach two and measure the relativistic mass of ...
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1answer
45 views

Relativistic mass of photon [duplicate]

What is the relativistic mass of one photon, i.e. what is $N$ here: $10^{-N}$ kg?
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1answer
75 views

Can $E=mc^2$ be used to find the energy stored in larger objects?

I know that $E=mc^2$ can be used to find the total energy of a particle but can it also be applied to larger things? Say a chair with a velocity $0$ $\frac{m}s$ and rest mass $10$ $kg$? Would the ...
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1answer
61 views

How does black hole suck light? [duplicate]

I was asked the same by my friend. I said that gravitational attraction also occurs for high energy particles . My friend said photon is not so very high energy particle which I found on net. He ...
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1answer
32 views

Matter - antimatter collision [duplicate]

I have read that when matter and antimatter collide they just cancel out each other with the emmision of bright light. But doesn't it violate law of conservation of mass? If the the atoms dissapear ...
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1answer
29 views

Where will the charge of a mass will go (having some net charge) when completely converted to energy?

All my confusion began while thinking of can charge be related to energy. Now Coulomb's law state that two body having some charges apply forces on each other which is true. And according to Newton $...
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91 views

relativity: accelerating a flywheel

Let's say we have a pair of flywheels rotating in opposite directions and they're inside a black box so that maybe we don't know that's what's inside, and we accelerate the box in the direction of ...
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4answers
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Does 'special relativity + newtonian gravity' predict gravitational bending of light?

It seems to me that special relativity (SR) already predicts that gravity will bend light rather than this effect being a proof of general relativity (GR). Photons have energy proportional to their ...
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1answer
82 views

How do we know relativistic mass also includes potential energy?

From Special Relativity it is shown that relativistic mass increases with kinetic energy, but how do we know potential energy is also part of relativistic mass? Is this a derived conclusion, or should ...
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74 views

What is the energy required to create a gravitational field equivalent to that a mass $m$ shows?

If the mass of a neutron star in its collapse becomes a singularity, then the resting energy of this gravitational field must be $E = mc^2$ ($m$ = star mass). Is this possibility wrong?
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Mass or inertia value depends on the velocity c, or the stars? [duplicate]

Ernst Mach influenced the physicists of his time and also Einstein, asserting that the inertia of objects depended on the presence of distant stars. If there were no stars in the sky, the objects ...
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4answers
81 views

Hypothetical mass-energy equivalence

2 questions: Hypothetically, if in an imaginary universe, the speed of light squared were 90% or 110% of what is is in our universe...would the math require another constant such as 1.1 or .9 next ...
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53 views

An object near the speed of light can become a black hole at high speeds? [duplicate]

If we use the Lorentz equation for the length contraction, and the Schwarzschild equation for the lightlike sphere, we can calculate the velocity for the object to form a black hole: $ \Delta x^{'}=\...
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How are mass, charge and energy all related?

An adequately energetic gamma ray photon can produce a pair of particles under the right conditions, one of these particles is an electron and the other one is positron. Pair production is widely used ...
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1answer
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Light has Mass or not? [duplicate]

If there is no mass for the light, it should penetrate. But light is not penetrating through solid medium. If the speed of light is constant there is some work should be done to maintain the speed. ...
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2answers
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Energy mass equivalence

Regarding $E=mc^2$, in a hypothetical parallel universe. If in that universe the speed of light squared were let’s say 10% slower, would everything still work but just slightly different? Or would an ...
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1answer
53 views

Does an atom gain mass when it absorbs a photon?

I understand the at rest a photon has no mass, but it has energy. So when a photon is absorbed by an atom the atom gains the energy of the photon. This captured energy raises the mass of the atom by ...
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3answers
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Problem in understanding energy-mass equivalence

From whatever approach (either from modern approach by Hamiltonian or from Einstein's original approach by considering momentum), we can derive that $p_{i} = \gamma mv_{i}$ and $$H = \gamma mc^2 = \...
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192 views

What is kinetic mass of photon?

Today an unusual thought stroke my mind. A mass moving will some velocity has energy called kinetic energy. Everyone knows that nature loves symmetry so why doesn't moving energy ( photon ) has mass ( ...
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1answer
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If mass and energy are same what will be the equivalent of a homogeneous ball in terms of energy and information?

We can observe an object with mass as it has a well defined boundary but it is not the same with energy. What may happen to the information or data that exists with an object and is needed to ...
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2answers
67 views

Can the origin of mass or inertia depend only of the gravitational field of matter? [closed]

The gravitacional field is directly proportional to mass or inertia. It doesn't have another property or field like this, with this power. I think that when we apply a force to an object, the ...
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3answers
173 views

If photons have no mass, how they create electrons and positrons on colliding? [duplicate]

How are electrons and positrons formed when photons collide, as photons are massless?
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1answer
38 views

Rest mass Increase and Elementary particles

When we usually talk about elementary particles such as electrons neutrinos etc... we mention their rest mass or their four vector mass which is invariant However how can we associate the "...
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1answer
38 views

Velocity and mass and particles

If mass increases as velocity increases how can I associate this with the fact that some particles such as neutrinos which barely have no mass, go faster when they have less mass or less interaction ...
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0answers
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Is the stopping power of a particle (as in Bethe Bloch formula) related to the total energy or to the kinetic energy only?

The average loss of energy in a material per unit lenght of a particle (in particular an electron, which is stable) is described by the quantity $dE/dx$. for ionization it is given by the Bethe-Bloch ...
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Relativistic mass of components gives system rest mass?

To put it briefly, in the classic thought experiment of a massless box with mirrored insides containing photons, does the relativistic mass of the photons imbue the box with rest mass? I take it that'...
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3answers
134 views

What is the rest/invariant mass of an electron?

An electron moves around the nucleus with a high speed. According to Einstein's theory of relativity the relativistic mass of a body is increases as it's speed increases. m=9.1×10^-31 kg shouldn'...
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1answer
64 views

Is the sun losing rest mass or relativistic mass?

It is commonly said that sun produces energy in the fusion process by converting mass into energy. If we disregard the concept of relativistic mass, how do we know whether the rest mass of the sun ...
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2answers
205 views

How can the total amount of energy in the universe be zero? [duplicate]

First of all, it is important to note that I'm not very savvy in neither general relativity nor any other area of expertise that answering this question may require. Therefore, I mean for the question ...
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Is spin really just “rest angular momentum”? [duplicate]

Spin is the intrinsic angular momentum of a particle. The particle itself is elementary and is not spinning on its axis, and has this momentum even at rest. The absolute magnitude of this momentum ...
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0answers
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An experiment about relativistic effect on weight

The draw explains everything. However I could not understand following: At the right side, since 2 masses move, the total mechanical energy is bigger(since potentials are the same, and kinetic is ...
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4answers
112 views

Problem with relativistic mass

We know that relativistic mass of a object is given by: $$m=\frac{m_{0}}{\sqrt{1-\frac{v^2}{c^2}}}.$$ So the mass of an object will become very large if it travels with a speed near to the speed of ...
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5answers
356 views

Why charge is Lorentz invariant but relativistic mass is not?

I have been reading Purcell's electromagnetism. In the text, he talks about conservation of mass, and charge; and invariance of mass, and charge. He says that charge is invariant because results of ...
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5answers
96 views

Why mass of nucleus decreases after binding of it's components (protons and neutrons)? [duplicate]

Nucleus mass should be equal to sum of mass of protons and neutrons, but after binding of these particles, its mass is reduced. Why? Due to reduced mass of protons or neurons? Then what's the purpose ...
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0answers
58 views

If the laws of physics weren't time/space translation symmetric, would energy/momentum still be meaningful quantities?

I've already come across Noether's theorem, that for every continuous symmetry in a Lagrangian there exists a corresponding conserved quantity and vice versa, with the standard examples of time ...
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1answer
59 views

Einstein $E=mc^2$ equation what if we found an element energy? [closed]

I started research in time travel idea soon and iam asking what if there exist an element that gives energy equals to c^2 in the equation is the mass of this element is 1 ( i don't know the unit ...
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3answers
58 views

Relation between mass and energy

I understand that the mass-energy relation in $E=mc^2$ means that a stationary body has rest energy,that can be converted into other forms. But why does this energy conversion have to result in a ...
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4answers
82 views

How can we calculate the speed from $E=mc^2$? [closed]

how can we calculate the speed of an object using the formula of Einstein $E=mc^2$?
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2answers
45 views

Why does nuclear fission release energy if individual nucleons are heavier?

You need to supply energy to separate nucleus, so if the nucleus was separated, shouldn't it have more energy(heavier)? If so, there won't have mass defect and will not release energy either. I am ...
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Is most mass from KE or PE?

I know most invariant mass is from the interaction of quarks with the gluon field, but is that kinetic energy or potential energy, or does this question not make sense? Am a college freshman but I ...