# Tag Info

## New answers tagged mass-energy

0

Matter-Antimatter annihilation and Hawking radiation of black holes are the two known examples of full or almost-full matter-radiation conversion. Notice that i avoid the term 'energy' as i think the term radiation is more appropriate

2

Actually, mass is not distinguishable. Or more precisely, it doesn't even make sense to talk about whether mass is distinguishable. Different kinds of particles are distinguishable, but the particle is not the same thing as the mass. Mass is just a property of a particle, just as energy is, or velocity, or momentum, or position.

3

Energy is a measure of a certain quantity well defined in the study of the behavior of nature. how is it possible that the energy that became one particle is completely indistinguishable from the energy that became a different type of particle. It is like asking about two sets of marbles "how come there are 19 marbles in one set and 19 marbles in the ...

0

Fission is exothermic only for heavy elements, while fusion is exothermic only for light elements. Intermediate nuclei, in the iron/nickel range, are the most tightly bound, and so you generally release energy moving in that direction. Fusing stable elements into uranium would consume energy, as would trying to break helium into hydrogen. For a more ...

1

What is conserved is energy and momentum, not mass. For a massive particle, mass is the energy at rest (when the particle is not moving) For instance in a 2 particles => 2 particles reaction, you will have: $E_1 + E_2 = E_3 + E_4$ $\vec p_1 + \vec p_2 = \vec p_3 + \vec p_4$ In the case of massive particles collisions at high energies, you have to use, ...

7

Energy and matter are not the same. Matter is a type of thing, whereas energy is a property of a thing, like velocity or volume. So your premise is flawed. In particular: there's no such thing as "a solid state of energy" - hopefully it makes sense that a property of something does not have states energy is not represented by waves, though it is a property ...

3

The thing about energy becoming particles is not entirely true. Quantum mechanics explains that particles themselves are waves. The energy that forms mass, however, is not a part of the particles themselves. For subatomic particles such as electrons and quarks, their mass is caused by their interaction with the Higgs field. The energy itself is stored in ...

0

Let's look at this from the non-relativistic perspective of Newtonian inertial mass. Inertial mass, the quantity $m$ in the equation $F = ma$, is the amount of inertia where inertia is, loosely, the opposition to change in velocity. The greater the magnitude of the mass, the less the acceleration for a given applied force. For ordinary, positive inertial ...

1

All depend on the context. If Dirac's theory of antiparticles one has get a negative energy, so why one should not use a negative mass if it is convenient for the formalism. For example, in semiconductor physics, the negative effective mass is related to the curvature of the dispersion law describing dependence of the quasiparticle's energy on its momentum. ...

3

You take any mathematical model that includes mass as a parameter, e.g. Newton's Laws, Special Relativity, General Relativity, etc, and put in the mass as a negative number. The model will then make predictions about what will happen, but because you have chosen physically unrealistic starting conditions the predictions of the model will be physically ...

1

First let's start with Newtonian mechanics, no relativity. The equation $E_p=mgr$ is only valid when $g$ is approximately constant, as it is near the earth's surface. If $g$ is varying like $1/r^2$, then we get $E_p=-GMm/r$. This energy is not interpreted as energy that belongs to the mass $m$ or to the mass $M$. It's interpreted as energy that is stored in ...

12

The answer is the there is some reduction in mass whenever energy is released, whether in nuclear fission or burning of coal or whatever. However, the amount of mass lost is very small, even compared to the masses of the constituent particles. A good overview is given in the Wikipedia article on mass excess. Basically, the mass of a nucleus will in general ...

1

The formula $\frac{m}{\sqrt{1-v^2}}$ is actually for the total energy, not the kinetic energy. The formula for the kinetic energy is actually $(\frac{1}{\sqrt{1-v^2}} - 1)m$. And if you do a Taylor expansion of this formula to second order, you'll find that you actually do recover $KE = \frac{1}{2}mv^2$. You get this from the aforementioned total energy ...

0

Well , the mass of the visible universe 6e51 kg contradicts this simplification . The HUP is an inequality. It tells you that the mass must be at least this small number you give, it does not put bounds from above, that is why it is immaterial for our classical existence. In addition the existing universe is not in a quantum mechanical virtual state, ...

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