Closed systems and mass/energy transference

In summary: However, this mass is usually not detectable as it is very small compared to the energy being transferred. The assertion that Einstein's equation is only valid for releasing nuclear energy is not entirely true as it also applies to the transfer of energy in other ways.
  • #1
Hobold
83
1
So I am reading a text written by my Thermodinamics professor and I find something that I still can't accept.

"(Sistema fechado) É aquele que não troca massa. (...) Um sistema fechado é dito isolado quando não troca energia. Entretanto, essa definição de sistema não é consistente com a teoria da relatividade, uma vez que quando energia atravessa a fronteira de um sistema, uma passa proporcional é também transferida segundo a equação de Einstein E=mc^2. (...)"

"(Closed system) does not transfer mass. (...) A closed system is said to be isolated when it doesn't transfer energy. However, this definition isn't consistent with relativity, as when energy crosses the boundary, there is a proportional mass being transferred as Einstein's E=mc^2 (...) However this amount of mass isn't anywhere close to detectable, as c^2 is sufficiently big."

I can't find this assertion to be true. I always thought Einstein's equation was only valid when releasing nucleus energy, such as through fission or fusion. I can't think how mass transference <-> energy transference would work, even if I consider mass as a parameter of the system (though it does not make sense to me).

Could anyone help me understand?
 
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  • #2
Mass has energy, and energy has mass. The energy entering the system brings its mass with it.
 

1. What is a closed system?

A closed system is a physical system that does not exchange matter or energy with its surroundings. This means that the total amount of mass and energy in the system remains constant.

2. How does mass transference occur in a closed system?

In a closed system, mass transference occurs through processes such as diffusion, convection, and chemical reactions. Mass can also be transferred through mechanical means, such as stirring or shaking.

3. What is energy transference in a closed system?

Energy transference in a closed system refers to the transfer of energy from one part of the system to another. This can occur through processes such as heating, cooling, or work being done on the system.

4. Can mass and energy be created or destroyed in a closed system?

No, according to the law of conservation of mass and energy, mass and energy cannot be created or destroyed in a closed system. They can only be transferred or converted into different forms.

5. How does the principle of entropy apply to closed systems?

The principle of entropy states that in a closed system, the total amount of disorder, or entropy, will always increase over time. This means that in a closed system, energy and matter will naturally spread out and become more evenly distributed, leading to an increase in entropy.

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