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

How are mass and density treated in general relativity? [duplicate]

Background: I am confused by how mass relates to the equations in general relativity. For example, given a certain mass density distribution, I am unsure how to express a system in terms of GR. ...
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1answer
119 views

Why is this nuclear reaction $p\to n+e^++\nu$ forbidden for a free proton? [closed]

Why is this nuclear reaction forbiden for a free proton? $$p\to n+e^++\nu$$ Where $p$ is the proton, $n$ is a neutron, $e^+$ is a positron, and $\nu$ is a neutrino. What i´ve been thinking is because ...
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2answers
128 views

Does electricity have mass?

Given a superconducting magnetic coil, such as the ones at the LHC, is there a difference in the coil's mass when it is powered down versus when is powered up? Edit: This has been labelled a possible ...
1
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1answer
205 views

Does the rest mass energy include the potential energy of the particle?

The potential energy (as far as I have studied - that is, mainly classical physics) depends on the reference level, since its absolute value cannot be calculated. It can therefore be negative as well. ...
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1answer
122 views

Would it be safe to say that mass is kind of a property of energy?

In a video i just saw about the true meaning of E=mc2, it said something that really got me thinking; "Mass is not really converted to energy" and that mass wasn't actually a thing, but more of a ...
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2answers
60 views

How do radio signals contribute to gravity?

First, the inspiration for this question: I just read that it takes one hour to send a picture from the New Horizons space probe, to Earth. It also takes around 5 hours for that picture to reach ...
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1answer
120 views

Will I weigh more if I have fever?

$E=mc^2$ means that energy is mass, and adding energy to an object (that is, making it hotter) makes it more massive. So if my body temperature increases, will I weigh more? or will i become lighter ...
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2answers
72 views

Does chemical energy contribute to mass? [duplicate]

Does chemical energy contribute to the mass of an object? I don't mean the bond energy, but the possible energy that could be released (i.e. Does an atom of oxygen and a molecule of hydrogen (H2) have ...
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1answer
678 views

Is $E=\hbar \omega$ correct for massive particles?

From Planck's relation we can say that the energy of a photon is $$E=h\nu=\hbar \omega \, .$$ where $\hbar \equiv h / 2\pi$. On the other hand, the energy of a free particle can be expressed as $$E=...
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2answers
173 views

In a nuclear reaction, where does the energy go?

Lets say two hydrogen fuse together, where does the energy released go? Is it carried away as momentum imparted on the helium atom? Is it carried away in neutrinos? Is it carried away as gamma rays? ...
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3answers
182 views

What experiments have been done that confirm $E=mc^2$?

What experiments have been done that confirm $E=mc^2$? Are there experimental results that contradict $E=mc^2$? Or are experimental results consistently showing this famous formula to be true?
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222 views

What happens to a particle and antiparticle that collide?

Matter can never be destroyed, so what happens to those particles? Do they just disappear? Where does the mass go?
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1answer
192 views

Mass loss for Fusion energy? [closed]

I am thinking how you can estimate the mass loss of the fusion energy for 1 kWh. I think you cannot use Einstein's $E=mc^2$ to calculate the mass loss in the fusion reaction of the Sun. How can ...
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1answer
122 views

Mass of a particle ( relativity)

A hypothetical atom has a rest mass of $15.000000136\,\mathrm{u}$. Overtime it undergoes a spontaneous breakdown into two masses of $7.000000229\,\mathrm{u}$ and $6.902727019\,\mathrm{u}$ respectively....
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1answer
70 views

Mass - Unification of kinetic and gravitational mass definitions

As a kinetic definition, mass of a body is a measure of the translational inertia of the body. There is also the gravitational definition of mass. Can these definitions (kinetic and gravitational) be ...
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2answers
859 views

Quarks in a hadron- where does the mass come from

We know that the sum of the masses of the quarks in a proton is approximately $9.4^{+1.9}_{-1.3}~\text{MeV}/c^2$, whereas the mass of a proton is $\approx931~\text{MeV}/c^2$. This extra mass is ...
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1answer
111 views

Do photons have no mass? [duplicate]

My Quantum Mechanics' teacher said today on the class that photons don't have mass. I was puzzled because I knew that photons have momentum. If a particle hasn't mass then its momentum sould be $0$ ...
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1answer
71 views

How does fusion work in the Sun if neutrons have more mass than protons?

According to my textbook, the next result of the fusion reactions in the Sun is: 4H -> He + neutrinos + gamma photons However, if hydrogen atoms are basically a proton and helium atoms are 2 protons ...
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2answers
158 views

Doubts regarding Einstein's 1905 derivation of mass-energy equivalence

This is a follow up on this question. In his [paper][2] under the title:Does the inertia of a body depend upon its energy-content, Einstein drives the famous $E=mc^2$ equation. His argument can be ...
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2answers
240 views

What is meant by mass defect of a single neutron or a single proton?

As per my understanding The mass defect of a nucleus represents the mass of the energy binding the nucleus, and is the difference between the mass of a nucleus and the sum of the masses of the ...
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1answer
105 views

What really happens when matter and antimatter combine? [duplicate]

When Energy is converted to matter, we know equal amounts of matter and antimatter are produced. What happens when matter and antimatter combine?
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2answers
120 views

Can matter be formed from nothing? [closed]

Well, I wanted to know whether matter can be created from nothing? Could matter be created in pure vacuum or does it require some energy? If energy is required, How is energy converted to matter? If ...
2
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1answer
182 views

How can we define energy? [duplicate]

Can we call matter without mass as energy? just a simple defintion to the word energy; massless matter= energy? and I'm not asking about photons.
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1answer
86 views

Mass and Schwarzschild Radius [duplicate]

Do free massless particles have a Schwarzschild radius? I'm curious about the mass in the equation for the Schwarzschild radius. I know that you can calculate a Schwarzschild radius for any massive ...
2
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4answers
155 views

Does a ticking watch have more mass? [duplicate]

In the video on YouTube, The Real Meaning of E=mc² | PBS| Space Time Studios, it claims that a ticking watch has more mass then a non ticking watch due to the intrinsic KE, PE and thermal energy of ...
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2answers
118 views

Where does the equation $p=\frac{1}{c}\sqrt{T^2 +2mTc^2}$ come from?

Where does the relativistic formula $$p~=~\frac{1}{c}\sqrt{T^2 +2mTc^2}$$ come from? What is the derivation from Einstein's formula? $T$ is the kinetic energy $m$ is the mass $p$ is the momentum.
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2answers
2k views

Do chemical bonds have mass?

When an exothermic reaction occurs, the energy in the chemical bonds of the reactants is partially transferred to the chemical bonds of the products. The remaining energy is released as heat. For ...
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1answer
85 views

How are photons effected by gravity? [duplicate]

If we use E²=m²c⁴+p²c², and we know mass of photon is zero, and they have momentum but why aren't they affected by gravity.
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2answers
120 views

How does a Black hole attract light? [duplicate]

Please no hate for lack of knowledge: I am somewhat fascinated with the subject of black holes. However, I do not understand a concept which is constantly attributed with black holes: that a black ...
4
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1answer
144 views

Binding energy and mass

I’ve been told that a greater binding energy means the nucleus is more tightly bound, and therefore that decreases the mass of the nucleus with respect to its nucleons when separated. But why does a ...
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2answers
59 views

Can a 0.1mm iron cannonball fired with a proportional cannon damage a tumbler (glass)? [closed]

A teammate just used the well known phrase "a storm in a teacup". I looked at my tumbler (full of water) and asked this question: "If a pirate ship the size of a nutshell had cannons with iron ...
4
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2answers
213 views

Is the Einstein Energy-Momentum equation $E^2 = p^2c^2 + m_0^2c^4$ valid only for Free Particles?

Is the energy -momentum relation $$E^2 = p^2c^2 + m_0^2c^4$$ satisfied only by free particles or even bound particles? Does the Energy refer to total Energy(including potential) or only (kinetic +...
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3answers
6k views

When an atom is split, what form of energy is released?

When an atom is split, what form of energy is released? All of the websites I have looked at say there is a lot of energy released when an atom is split, but it never says what form of energy it is in....
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1answer
544 views

Why does the electron volt seem inconsistent with mass?

If I understand correctly, an electron volt is the work done when an electron is moved from a plate with a voltage of 0V to another plate with a voltage of +1V. This is represented by $V = W/Q$, or $W ...
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2answers
331 views

Can change in temperature cause a change in mass of an object?

If a gold bar is heated to say 200 degree Celsius then will it have the same mass at say 10 degree Celsius. Does energy has mass? If so then does this increased 'heat energy' cause an increase in the ...
2
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3answers
199 views

Stability of nuclides in regard to the forces acting upon its nucleus

I am having trouble piecing together some information regarding the stability of a nucleus. I have read that iron-56 is the most stable isotope, because it has the highest binding energy per nucleon ...
2
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4answers
385 views

Coupling fission and fusion and disappear all mass. Why doesn't this happen?

I'm confused about the fact that in a fission process the masses of the "products" are less than the mass of the "reactants". And in a fusion process the masses of the "products" are less than the ...
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2answers
75 views

Do photons have/contribute to mass?

Do electrons gain mass by absorbing photons during excitation and releasing them by returning to the ground state? Do photons have mass in the form of energy by $E=mc^2$?
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2answers
91 views

Can we create heavier particles with high energy?

It is known that an electron and a positron are created from the energy of gamma ray, is it possible to create heavier particles like proton and neutron from the energy of gamma ray? (if so what is ...
3
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1answer
158 views

Where does this relation between gamma, energy and mass come from?

I am doing a course that has used this relation a few times now: \begin{equation} \gamma = \frac{E}{mc^2} \end{equation} It makes sense physically, when $E = mc^2$ the particle is at rest and $\...
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5answers
406 views

Can dark matter be converted to dark energy?

According to energy mass conversion law, mass can be converted to energy. So is it possible to convert dark matter into dark energy?
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2answers
577 views

Why doesn't Beta Decay violate the laws of physics?

In Beta decay, a neutron decays into a proton, and "throws out" an electron at high speed. However, this, to me, suggests that the law of conservation of mass is not being kept here. Neutrons have a ...
1
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1answer
60 views

Mass-energy-equivalence's effect on SI units?

Maybe I'm misunderstanding mass energy equivalence, but can we use it to get rid of the Joule (or the kilogram) and have a single unit for both? It seems weird that if they're equivalent they'd have ...
2
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3answers
164 views

Does (mass $\rightarrow$ pure energy) conversion need both matter $and$ antimatter?

A question in my revision guide: "Explain why the mass of a tree cannot be converted directly into energy." The answer explains that the tree contains particles but not their corresponding anti-...
0
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2answers
241 views

How does electron gets negative charge and proton gets positive charge? [duplicate]

I researched much in physics but I still do not know how does electron gets negative charge and proton gets positive charge? What is the source of this charge and energy? How can this particles ...
8
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5answers
449 views

How to derive $E=mc^{2}$?

Is there some way to derive $E=mc^{2}$? I can understand that energy in something is proportional to its mass, but the $c^{2}$ part. I have no idea. It seems like the way the units are going it would ...
25
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3answers
6k views

Why can't I do this to get infinite energy?

I know that I cannot do this because of conservation of energy, so I am looking for an answer as to why this will not work. So by my understanding of Einstein's whole famous $E=mc^2$ thing it is ...
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2answers
51 views

Does Energy have a similar effect on time as Mass would when considering the gravitational field both exert?

I was thinking about light and the different frequencies. The higher the frequency the more energetic the photon. The higher frequency photon being more energetic seems counterintuitive when ...
0
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2answers
131 views

Semi-empirical mass formula

The mass formula is given by $M(Z,A) = ZM_{p}+(A-Z)M_{n}-a_{1}A+a_{2}A^\frac{2}{3}+a_{3}\frac{Z(Z-1)}{A^\frac{1}{3}}+a_{4}\frac{(Z-A/2)^2}{A}+a_{5}A^\frac{-1}{2}$ So I am just wondering here what ...
0
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1answer
71 views

Mass of an Atom

So the mass deficit of an atom, denoted by $\Delta M(Z,A)$, is given by the following formula, $\Delta M(Z,A) = M(Z,A) - Z(M_{p} + m_{e}) -NM_{n}$ However since the rest mass of an electron is a lot ...