Classical mechanics refers to the classical (i.e., non-relativistic, non-quantum) study of physics. Three major formulations of classical mechanics are newtonian mechanics, lagrangian mechanics, and hamiltonian mechanics. The latter two are rather useful in extensions to Classical Mechanics; ...

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Motion of water droplets on airplane window during takeoff

I observed this while on a flight that took of shortly after it had rained, but could not understand why it happened. The windows of the aircraft had drops of water on the outside. As the flight ...
-3
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0answers
38 views

Movement of a box containig a particle [on hold]

A small thought experiment: Imagine a rectangular box in space, containing particle, all resting at $t=0$ from your point of view. At some point in time $t>0$ the particle starts to move with ...
-2
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0answers
22 views

Numerical solution of Duffing’s equation [on hold]

Any one can help me with the Numerical solution of Duffing’s equation on urgent basis as i need this for my exam.
0
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0answers
12 views

Movement of a bobbin thread when pulling it's thread at certain angles [on hold]

The problem: You try to move a bobbin thread by pulling it by it's thread. If you pull it while the thread is horizontal it slides your way but if it is at an angle the bobbin thread starts rolling ...
0
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1answer
58 views

Determining constants of motion for this Hamiltonian? [on hold]

Let $S$ be a Hamiltonian system with three degrees of freedom, let $q_1, q_2, q_3$ be the generalized coordinates. Suppose the Hamiltonian of the system is $$ H = \alpha \sum_{i=1}^3 p_i + V(q_1^2 + ...
6
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4answers
135 views

Will a tennis ball go further if i hit it with the side of the racket?

If i hit a tennis ball 'properly' on the stringing, does it go further than if i rotate the racket 90 degrees in my hand and hit the ball with the same force, but on the side of the frame? I'm ...
-1
votes
0answers
25 views

Name of steel alloy according to AISI [closed]

I need a list of steel alloy with the percentage of the alloy elements...or if anyone know the name of steel alloy contains 0.15% C, 0.043% Si, 1.78% Mn, 0.45% S, 0.13% Ni, 0.24% Cu and 96.8% Fe ? ...
-2
votes
1answer
35 views

Pitch of an object on a inclined plane [closed]

I've been struggling to figure out a solution for this. Let's assume a sequence of slopes, each with a certain incline (positive or negative) and length. Say we have the pitch angle of a object(e.g. ...
15
votes
4answers
326 views

Why don't hexapods gallop?

I haven't observed any terrestrial hexapods that gallop like agile tetrapods(cheetahs/horses). Instead, I've observed that all of them scuttle which constrains their maximum velocity. And after ...
3
votes
1answer
49 views

Ehrenfest Theorem and boundary Conditions

In what cases does Ehrenfests Theorem hold? If I look at the wavefunction of electrons in a squared box of length $L$ (with periodic boundary-conditions, $\Psi(0) = \Psi(L)$), then the solution to ...
0
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0answers
13 views

Fracture Mechanics: Relation between delamination and incident pressure

I am working with thin film self replicating cracks wherein a film is placed on a substrate, and the delamination and crack propagation occur simultaneously. I intend to map out the force vector field ...
2
votes
3answers
63 views

Sliding sphere wear shape

Please refer to the figure attached. Consider a normal force is acting on the top of sphere. A constant coefficient of friction causes frictional force throughout the sliding. I want to know after ...
0
votes
0answers
26 views

In d'Alembert's principle, how that the Reverse effective force and Force of constraints are different?

In d'Alembert's principle, how that the Reverse effective force and Force of constraints are different? Both are opposition or restriction on the body but how both be different in real?
5
votes
1answer
56 views

How to popularly describe typical features of a “non-linear system”

To quote Physics.SE tag definition: The term non-linear or nonlinear has several definitions but is generally used to describe a system that cannot be approximated by a superposition principle or ...
2
votes
0answers
27 views

On the Liouville-Arnold theorem

A system is completely integrable (in the Liouville sense) if there exist $n$ Poisson commuting first integrals. The Liouville-Arnold theorem, anyway, requires additional topological conditions to ...
2
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0answers
82 views

Does the motion of a free electron in a plane wave electromagnetic field have analytical solutions?

Does the motion $[x(t), y(t), z(t)]$ of a free electron in plane wave electromagnetic field have analytical solution (oscillating E and B fields)? The Lorentz force is : \begin{align}m_e\begin{...
1
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0answers
47 views

Hamiltonian formulation of the semiclassical Model of electrons

I'm currently reading the book Solid State Physics by Neil W. Ashcroft and N. David Mermin. In Chapter 12 they introduce the "Semiclassical Model of Electron Dynamics". In short: After having solved ...
1
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4answers
42 views

Particle Equilibrium and the Interpretation of Accelerations

I have a simple question regarding the interpretation of acceleration and force in the context of a particle in equilibrium. Given that the necessary and sufficient definition for particle equilibrium ...
-3
votes
0answers
39 views

Would it be possible to foresee the quantum theory via this thought experiment?

If the Newtonian understanding of universe (I only mean the philosophical understanding, not the scientific theory) would be correct, then we could build a machine that can observe the solar system ...
0
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0answers
56 views

Analysis of this hyperstatic system - how can I calculate it?

I have the following real-world situation (superior view): A rigid rectangular plate is bolted to the ground by four bolts in a rectangular array; A force F is ...
4
votes
2answers
108 views

Motion of a bouncing sphere with a spring attached inside

Imagine a sphere with inside a spring attached (between opposite sides). You let it fall from a certain height, after which it bounces from a flat surface. The sphere is rigid. Will the following ...
0
votes
0answers
31 views

To find the conserved quantities in a lagrangian?

Lagrangian of a particle of mass $m$ is given by $$L= \frac{m}{2}[(\frac{dx}{dt})^2 + (\frac{dy}{dt})^2 + (\frac{dz}{dt})^2]-\frac{V}{2}(x^2+y^2)+ W\sin(\omega t)$$ Is energy conserved here since ...
1
vote
1answer
124 views

Eigenvalue equation for kinetic and potential energy

In Boas' Mathematical Methods there is a section on linear algebra in which it is stated that we can write the eigenvalue equation for a set of springs using the kinetic energy and the potential ...
1
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3answers
55 views

Two Rolling logs

Suppose we have two logs rolling down a hill, one of gold and the other of wood; the acceleration for both will be equal, something which is unclear to me; I get that this may be due to their form, ...
0
votes
0answers
63 views

Conservation of energy?

Consider a weightless vertical rod hinged at its center. Two identical inflated balloons are tied at each end of the rod. Entire system is under influence of gravity and is in air, so there are ...
-5
votes
1answer
72 views

What happens in this collision? [closed]

First, I describe a simple contraption. Second, I describe a simple collision. Third, I replace a box in the collision with the contraption and ask whether, "What happens after the collision?"-i.e., "...
0
votes
1answer
66 views

How to find the corresponding Hamiltonian in quantum, if Hamiltonian in classical mechanics is given? [closed]

Hamiltonian in classical mechanics is $$H=wxp $$ $x=$ position, $p=$ momentum coordinate. Find the corresponding Hamiltonian in quantum mechanics!
0
votes
1answer
52 views

Center of percussion and sweet spot

I understood, when a ball is made to strike at the "center of percussion" of a baseball bat, the batter will not experience a perpendicular reaction force. Could I regard the center of percussion as ...
1
vote
1answer
32 views

What means that a pendulum system having saddle points? [closed]

What means that a pendulum system having saddle points? I know when it haves drain, source but I can't find any information of when it has saddle points
1
vote
1answer
73 views

How is this Lagrangian derived? (Lagrangian with an exponential function)

In the second answer of this post, Euler-Lagrange equations and friction forces I see a normal Lagrangian (T-V) times an exponential function. $${\cal L}=e^{t\gamma/m}\left(\frac{m}{2}\dot{x}^2 -U(t,...
-4
votes
1answer
87 views

A brief idea about Noether's Theorem? [closed]

I've recently been lead to believe that a certain "Noether's Theorem" could prove to be a very helpful tool in physics. I've only just started reading up on Lagrangian mechanics, but I'd like to get ...
0
votes
1answer
129 views

Classical Mechanics as an approximation of Quantum mechanics [closed]

I want to show an equality: We know from Ehrenfest's theorem that $$ \frac{d \langle x \rangle(t)}{dt}= \left\langle \frac{\partial H}{\partial p} \right\rangle $$ I'd like to derive the ...
1
vote
1answer
22 views

Why does the colour inside a discharge tube change as pressure reduces?

Observing cathode ray tubes at various pressures, I see a transition from a violet/purple colour at 10-40mmHg, transition to a white/light blue colour at lower pressures. Any idea why this happens? ...
0
votes
1answer
42 views

counting normal modes

I'm not sure if my confusion is substantive or merely semantic. So here's the most naïve way to frame it: A free $N$-atom molecule has $3N-6$ vibrational normal modes, with each mode having fixed ...
0
votes
2answers
54 views

Can I give a table tennis ball enough spin so that it rolls further on the other side instead of bouncing?

If I give a table tennis ball enough topspin, is it possible that the ball on touching the other side of the table doesn´t bounce, but just rolls further?
1
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0answers
40 views

Reason behind Poincare's generalisation of the law of inertia

In Poincare's Science & Hypothesis [Chapter 6], he starts with Galileo's famous ($1$) Principle of Inertia — A body acted on by no force can only move uniformly in a straight line. He then ...
0
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0answers
13 views

a/x^2 + bdx^2 analytical solution [migrated]

I have this physics problem I'm trying to solve and its been a while since I've done differential equautions. The problem I'm trying to solve is : ...
0
votes
0answers
21 views

Pseudo acceleration when both observer and observed body are accelerating and also the surface is accelerating

Today we were taught us the concept of pseudo forces.I understand that suppose when the observer is in an accelerated reference frame to make newtons laws valid we consider an acceleration in the ...
2
votes
0answers
22 views

Examples of multiply-connected compact configuration spaces

I'm a looking for examples of dynamical systems that have multiply-connected compact configuration spaces. Since I'm not a 100% sure about the correct terminology for the systems (I am sure about the ...
10
votes
1answer
366 views

In quantum mechanics, how exactly do we associate Hermitian operators to classical observables? [duplicate]

In a first course on quantum mechanics, everybody learns some version of the following statement: Postulate: To every classical observable $A$ of a physical system, there corresponds a Hermitian ...
0
votes
1answer
34 views

Composite materials [closed]

I'm reading about brake pad material. The paper said ...according to original equipment manufacturer (OEM) the pads are made by combining five types of materials: binders, abrasive, performance, ...
5
votes
0answers
123 views

Geometric point of view of configuration space and Lagrangian mechanics

Even though (I think) I understand the concept of a tangent bundle, I have trouble assimilating the idea of the configuration space being one and in relation to what that is the case. How can I ...
0
votes
0answers
30 views

What enclosed geometry amplifies sound the most?

I am going to build a record player. It will read sound electronically but I also want it to be able to project sound mechanically, like a classic record player. So if sound enters a tube, can you ...
-1
votes
1answer
47 views

Why do molecules have $3N-5$ or $3N-6$ degrees of freedom?

In linear molecule, it has $3N-5$ degree of freedom in vibration mode and $3N-6$ in non-linear molecule. I can get idea about $5$ and $6$ which is related to translation and rotation but I cannot ...
-1
votes
0answers
12 views

Chromatic confocal microscopy (CCM) and stylus probe

I read research that compared between chromatic confocal microscopy (CCM) and stylus probe in wear test but the research didn't clearfield what is chromatic confocal microscopy and what is the stylus ...
0
votes
1answer
24 views

The directions of the frictional force acting on the cylinder while ascending and descending cylinder

A cylinder rolls up an inclined plane,reaches some height,and then rolls down without slipping throughout these motions.The directions of the frictional force acting on the cylinder (A)While ...
-2
votes
1answer
67 views

Competition Physics Book for High School Physics

I am currently a high school physics student who has recently started participating in some physics competitions. Although I have an alright understanding of the physics and mathematics and can ...
5
votes
1answer
57 views

Why does galilean invariance imply that particles that start rest stay on the same line?

I'm reading Arnol'd for self study. I'm struggling with this question: "Show that any system of two particles will remain on the same line that connected them at the initial moment, if they started at ...
0
votes
1answer
21 views

Wear rate with sliding speed

I read so many research studying the effects of sliding speed on wear using pin on ring testing machine all of papers said: when the sliding speed increase the wear rate will increase because the true ...
1
vote
2answers
39 views

Lagrangian mechanics not relying on time or independent of time [closed]

If neither the potential energy nor kinetic energy depends on time, then Lagrangian is explicitly independent of time I find this statement a little bit odd because velocity is distance over time or ...