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15 votes
2 answers
3k views

Hysteresis and dissipation

Hysteretic phenomena are often linked to dissipation. When there is a hysteresis loop, the dissipated energy can usually be computed as the area of the cycle. For example, in ferromagnetic materials, ...
Georg Sievelson's user avatar
5 votes
1 answer
1k views

What is the reason of hysteresis loss?

Consider a ferromagnetic material is subjected to a gradually increasing external magnetic field and magnetized to saturation. Then a reverse field is applied to demagnetize the material and then the ...
SRS's user avatar
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4 votes
2 answers
949 views

Dissipative forces and reversible processes

A book that I have contains the following lines: For a process to be reversible, the dissipative forces such as viscosity and friction should be absent. My question is why?
user avatar
2 votes
1 answer
129 views

Explanation of a spring using "Artistotle's law of motion", $\vec{F}=m\vec{v}$

So I was watching Susskind's Classical Mechanics lectures and I didn't understand something in the second lecture. He was telling about Aristotle's Law of motion which is $$\vec F = m\vec v.$$ He ...
Harshit Joshi's user avatar
1 vote
1 answer
332 views

Absence of dissipative forces in a reversible process

I can't understand why dissipative forces must be absent during a reversible transformation. Aren't they a way of exchanging heat with ambient? Since the system is allowed to exchange heat with the ...
Stefan's user avatar
  • 25
0 votes
3 answers
1k views

Why does the reversible adiabatic expansion do more work on the surroundings compared to the irreversible adiabatic expansion?

I am wondering why a reversible adiabatic expansion results in a higher work output on the surroundings though the irreversible adiabatic expansion has to overcome the frictional force and therefore, ...
Anna Dapont's user avatar
0 votes
1 answer
65 views

Why are simple models of coupled pendulums incapable of describing irreversible energy dissipation?

Consider two pendulums $A$ and $B$ coupled by a spring and also regard $A+B$ to be a completely isolated system. Let us start the system in an initial configuration where only one of the pendulums (...
SRS's user avatar
  • 27.2k
0 votes
2 answers
1k views

Why must all natural processes be irreversible?

My thermodynamics lecturer was talking about reversibility and the idea of spontaneous change and he mentioned that all natural processes are irreversible. Can someone offer some sort of proof or ...
Vishal Jain's user avatar
  • 1,545
0 votes
3 answers
492 views

What happens to the heat generated in an irreversible process?

I know that a reversible process does more work than an irreversible process and that extra work is turned into heat. But what does that heat do? Does it increase the temperature?
user145010's user avatar
0 votes
0 answers
30 views

Asymmetry when $t\rightarrow -t$ [duplicate]

If we consider the equation of critical damping $$x=(a+bt)e^{-ct}$$ then the graph is However, it is asymmetric for positive and negative time values. I have an intuition that this should be the case ...
GedankenExperimentalist's user avatar
0 votes
0 answers
42 views

Reversibility of equation $F=mv$ [duplicate]

Please read the following text. This text is part of Leonardo Sauskind's book. It says that the relation F = m v is reversible. Why?
Mkrueger's user avatar
-1 votes
3 answers
2k views

Why do energy transfers always result some heat loss?

explain that energy transfers and transformations in mechanical systems always result in some heat loss to the environment. Like why is it necessary for a heat loss?
CountDOOKU's user avatar