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Equivalence of various definitions of reversibility in classical mechanics

I was reading Classical Mechanics: The Theoretical Minimum by Leonard Susskind, and the definition of reversibility in that was: Given a state of a system, then we know exactly what state it came ...
Neeladri Reddy's user avatar
0 votes
1 answer
105 views

Is determinism broken in special relativity?

Under classical mechanics, in an isolated system everything is deterministic given some initial conditions. Otherwise, we would have to consider some probabilities of interactions with the outside on ...
zetzar's user avatar
  • 91
5 votes
1 answer
354 views

Are Hamilton's equations reversible?

Say I define a time dependent vector field $\Psi(t):\mathbb{R}^d\to \mathbb{R}^d$ as reversible (also here) if, for $f(x,y)=(x,-y)$, we have: $$ f\circ \Psi \circ f =\Psi(-t)=\Psi^{-1}(t).$$ Just to ...
blobman man's user avatar
0 votes
2 answers
96 views

Is this set up a reversible process and is the adiabatic equation of state applicable here?

I had this question in a recent test: My teacher while discussing this question used the adiabatic equation of state PV^gamma=constant to solve for length L (options C and D). And used work energy ...
utkarsh's user avatar
  • 115
3 votes
1 answer
132 views

How does coarse-graining lead to irreversibility?

This is how I used to understand how coarse-graining leads to irreversibility. Suppose that we start with a coarse-grained phase space and two initial conditions belonging to two different phase cells....
Solidification's user avatar
4 votes
1 answer
1k views

Reversibility of Hamiltonian dynamics

I'm trying to understand a very basic property of Hamiltonian dynamics. I don't have a physics background but I do know some mathematics. I want to understand why negating the momentum is equivalent ...
5d41402abc4's 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
3 votes
1 answer
492 views

What is "irreversible displacement"?

In this Wiki page on D'Alembert Principle they say that "The principle does not apply for irreversible displacements, such as sliding friction, and more general specification of the irreversibility is ...
user avatar
1 vote
0 answers
42 views

Why is it impossible to remove the crease from folded paper? [duplicate]

Suppose I have a normal A4 paper sheet and I bend the paper in two. My question is: Why the paper now have this line and why the paper didn't lose naturally this line? My conjecture: I was ...
user avatar
3 votes
4 answers
249 views

Irreversibility Aristoteles law of motion

I am watching the second lecture from the theoretical minimum and do not understand the argumentation of Susskind. For those who do not want to watch the video. It is about the law of motion from ...
bodokaiser's user avatar
3 votes
2 answers
2k views

Reversibility in classical mechanics

I am watching Susskind's 'Theoretical Minimum' videos. At one point in his course on classical mechanics (2nd video if I remember correctly) he affirms that Netwon's second law of motion makes ...
user3419556's user avatar
8 votes
1 answer
1k views

Why must allowable physical laws have reversibility?

I'm watching Susskind's video lectures and he says in the first lecture on classical mechanics that for a physical law to be allowable in classical mechanics it must be reversible, in the sense that ...
Gold's user avatar
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