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].
192 questions from the last 365 days
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Physical significance of $(m_x,m_y)=(\frac{\sum m_i x_i}{\sum x_i}, \frac{\sum m_i y_i}{\sum y_i})$ [closed]
What is the physical significance of $$(m_x,m_y)=(\frac{\sum m_i x_i}{\sum x_i}, \frac{\sum m_i y_i}{\sum y_i})~?$$
The equation looks like the one of center of mass. There we calculate, the point ...
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D'Alembert's Principle and its relation to the derivation of Lagrangian mechanics
In this YouTube video "Lagrangian Mechanics: when theoretical physics got real" by Dr. Jorge S. Diaz showing the derivation of Lagrangian mechanics, d'Alembert's principle, which generalizes ...
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Is there a mistake in Susskind's "Theoretical Minimum" in chapter 4 "Systems of More than One Particle"?
On page 86, it says:
... the force on any one particle is a function of its location as well as the location of all the others. We can write this in the form
$$\vec{F}_i = \vec{F}_i(\{\vec{r}\})
$$
...
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1D relativistic motion under a $k/x$ potential, oscillations? [closed]
I'm solving a problem preparatory to the (special) relativistic motion under central forces.
We consider a particle of mass $m$ under an attractive potential $\frac{k}{x}$, with $k < 0$.
If the ...
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2
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0
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53
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Poisson bracket form of an equation in generalized hydrodynamics
This question talks about generalized hydrodynamics (GHD) (a relatively new field that studies non-equilibrium integrable systems).
In generalized hydrodynamics (GHD), the main EOM is the Euler-...
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81
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Emergence of macroscale Generalized Hydrodynamics (GHD) from microscale integrable systems: How is this possible?
I am trying to wrap my head around Generalized Hydrodynamics (GHD) (see, for example, the 2024 plenary lecture The equation of generalised hydrodynamics by Prof. Benjamin Doyon [1]) and how it applies ...
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How to correctly compute angular momentum of a cone rolling on a horizontal surface? [closed]
I’m trying to understand the angular momentum of a solid cone rolling on a horizontal table without slipping, and I’m running into confusion about how to define it properly.
Consider a uniform solid ...
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3
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Does the Work-Energy Theorem apply to thermal kinetic energy, or is thermal $ΔE_k$ exempt from $W = ΔE_k$? [closed]
Mainstream physics teaches three statements as foundational:
Fact 1: Temperature is proportional to average kinetic energy of particles: T ∝ ⟨Eₖ⟩
Fact 2: Heat transfer causes a change in kinetic ...
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0
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Axiomatic Equivalence of Theories [duplicate]
It's often stated that classical mechanics has three equivalent formulations which are very well understood:
Newtonian Mechanics
Lagrangian Mechanics / Least Action Formulation
Hamiltonian Mechanics
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2
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3
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Newton's action reaction and relative movement of connected masses
Imagine the following naive scenario: Consider two point masses (eg idealized solid spheres) $M_1$ and $M_2$ connected via a massless (again idealization of course) solid bar or rod (...like a ...
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2
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1
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Why can't we use an on-shell action as a function of initial data only?
I will start explaining how I understand the use of the on-shell action. Then I will ask my question
On-shell action
Consider a system with an action functional
\begin{equation}
S[q,p]= \int p_i dq^i -...
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2
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99
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Catamaran moving in reverse with a crosswind
I have been busting my head with this one. I have found one video explaining this and to my understanding the answer is wrong, hence I am seeking help to truly understand physics once and for all.
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Proof verification for the necessary condition for a generating function to be a "generating function"
For a type 1 generating function $F(q,Q,t)$, the defining equations for a canonical transformation are
$$p_i = \frac{\partial F}{\partial q_i}(q,Q,t) \equiv f_i(q,Q,t), \qquad P_i = -\frac{\partial F}{...
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What does “path independence” mean in the definition of a conservative force? [duplicate]
I have a conceptual question about conservative forces.
Textbooks often state that if a force is conservative, then the work done by the force in moving a particle from point $A$ to point $B$ is ...
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1
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1
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Rigorous definition of constraints in Lagrangian mechanics
I am currently taking a course in Analytical Mechanics and my professor uses Goldstein's 'Classical Mechanics' and I am dissatisfied with how constraints are introduced there. The discussion is mostly ...
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