Questions tagged [classical-mechanics]
Classical mechanics discusses the behaviour of macroscopic bodies under the influence of forces (without necessarily specifying the origin of these forces). If it's possible, USE MORE SPECIFIC TAGS like [newtonian-mechanics], [lagrangian-formalism], and [hamiltonian-formalism].
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A problem with momentum conservation (Newtonian and relativistic) [closed]
Assume we have a large parallel-plate capacitor with a very high, uniform electric field. A nonconductive bar joins the plates at their centers. Now, assume that two small charges with negligible ...
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Transforming Initial Cartesian Uncertainty into Delaunay Variables for Orbital Uncertainty Propagation [closed]
I am working on orbital uncertainty propagation where the initial uncertainty is given in Cartesian coordinates
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(r,v), either as a covariance matrix or as bounded (non-statistical) ...
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A (probably wrong) proof that the fundamental Poisson brackets are independent of the special choice of the canonical variables
In Wolfgang Nolting's book Theoretical Physics 2 - Analytical Mechanics, the following theorem is stated:
While the formal definition of canonical trasformation is given only several pages later in ...
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Is there a connection between Ehrenfest equation and von Neumann equation? [closed]
I understand how Ehrenfest is sort of giving a correspondence between classical and quantum whereas von Neumann is more like a quantum mechanical equivalent of Liouvilles equation. But do they share ...
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Using conserved quantities as variables in Mechanics
I am currently taking a course in theoretical (classical) Mechanics, where I have learned about the Darboux theorem. My professor has also mentioned one can "reduce the system by symmetry", ...
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Model of hitting a mosquito [closed]
I was thinking how could we model the attempt of hitting a mosquito standing on a wall. The mosquito (a point P) is standing on a wall (a plane) and we are trying to hit it with an object of area A ...
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Classical mechanics vs quantum mechanics [closed]
In classical mechanics we say that a classical particle obeys the equations of motion, whereas in quantum mechanics a particle can take any path, not just the classical one. But when we quantize a ...
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Bargmann–Michel–Telegdi (BMT) equation derivation?
What is the relativistic equation capturing the equation of motion of an electron going through the Stern-Gerlach experiment in classical mechanics? After some googling it seems I'm after a derivation ...
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Could 3I/ATLAS be a fragment from a collision involving a TNO and an interstellar object?
Observations of 3I/ATLAS (C/2025 N1) suggest a highly anomalous object, distinct from both typical comets and previous interstellar visitors. Rather than proposing an artificial origin, I would like ...
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Mass lifting off a harmonic oscillator
Consider this setup:
A classic, harmonic oscillator made of a spring with spring constant $k$ and a mass $m_1$ that oscillates vertically. $m_1$ is formed like a horizontal plate, and on the plate ...
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How come the fact that momentum is a covector does not contradict its coordinate change law?
First of all, I am aware of existence of this question, as well as other relevant questions at MSE and PSE. However, all answers to those questions focus too much on why momentum can take a vector as ...
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How can one see the disappearance of entanglement as one transitions from a quantum to a classical system?
I am trying to combine two concepts in this question: quantum entanglement and the deformation quantization.
From the definition of entanglement on Wikipedia:
Consider two arbitrary quantum systems $A$...
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Measuring mechanical power of a PMDC electromotor
So I have this problem. I want to measure the efficiency of an experimental PMDC motor. As you know 𝜂 = P_out / P_in, in the case of a PMDC: 𝜂 = P_mech / P_el. P_el = VI, but P_mech is a problem. I ...
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How to minimise jettisoned mass spent for a body with continuous but variable thrust?
In general I would like to know how to minimise fuel mass spent for an orbiting body that continuously jettisons its mass (i.e. ion thruster) so as to perform efficient transfer maneuver in ...
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Why do “points” in phase space correspond to possible physical states of a system, rather than “lines”?
Why aren't “lines” the physical states of system, instead of “points”? In a simple harmonic oscillator, the motion of particles changes back and forth between kinetic and potential energy, but it ...
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