# Tagged Questions

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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### 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 ...
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### Mechanics Landau Galilean Principle

I started reading Landau's Mechanics book and was having some trouble understanding the Galilean Relativity Principle. What does Landau mean by saying space to be homogenous and isotropic and time is ...
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### 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 ...
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### can there exist an imaginary pivot in mechanics?

Can there exist an imaginary pivot in mechanics. for example there is a mass attached to a rod of length l? so the pendulum can move in a fixed plane.now my question is that can there be a pivot ...
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### What is the tension on the horizontal rope in this conical pendulum setup? [on hold]

A rope is attached to the top of a straight pole. A person of 890N and a seat of 201 N are attached to the end of this rope. The person rotates 37.4 revolutions/min in the horizontal plane while the ...
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### 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 ...
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### Lagrangian mechanics not relying on time or independent of time [on hold]

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 ...
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### Physics behind seemingly-impossible “rice bowl suction” Guinness world record? [duplicate]

By pressing a rice bowl on his abdominal muscles, Zhang Xingquan was able to create enough suction to pull a 36.15 tonnes heavy train for 40 meters Source: Guinness world records website. How does ...
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### Simplest Live Demonstration of Adiabatic Transport

I have to give a presentation on Berry phase. I would like to give the simplest live demonstration of adiabatic transport. If I move an object in a loop and return that object back into its original ...
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### Too big to revolve like an atom? [on hold]

At what point do objects naturally start revolving as a disk? From an atom, with which the electron revolves as a sphere, to a galaxy, that revolves in the same direction? I herd about rigid ...
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### Newton's third law, weak and strong law of action and reaction [duplicate]

In the case of a system of moving charges forces between charges is obtained by Biot-Savart law. But it violates both action and reaction law. How can we prove that?
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### What is momentum really?

Wikipedia defines momentum as in classical mechanics: In classical mechanics, linear momentum or translational momentum is the product of the mass and velocity of an object. However, an ...
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### Projectile question doubt [on hold]

A hunter wants to shoot a monkey with an arrow by launching the arrow at a speed $v_0$ at a distance of $L$ from the base of a tree of height $H$ on which the monkey is sitting. Now on watching the ...
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I am looking for a book about "advanced" classical mechanics. By advanced I mean a book considering directly Lagrangian and Hamiltonian formulation, and also providing a firm basis in the geometrical ...
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### Which makes for a better equivalent capacitor? In series or in parrallel? [on hold]

I understand how capacitors in series and in parallel work. However, I am wondering if it makes a difference, in terms of making a better capacitor that can store more charge, would you connect them ...
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### Tilting a table

Let us say we have a perfectly horizontal table which has a cube placed on top of it. Furthermore, the cube is hollow and the sides weight is negligible. Now, what is the maximum angle that I can tilt ...
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### Classical limit of quantum mechanics

I have heard that one can recover classical mechanics from quantum mechanics in the limit the $\hbar$ goes to zero. How can this be done? (Ideally, I would love to see something like: as $\hbar$ ...
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### How does the bowling computer know I'm right handed? [on hold]

I went bowling the other day and after I rolled my first ball I was suprised it was written on the screen that I was "right-handed". How was that figured out? My first guess is that there is ...
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### Why does most galaxies resemble a 2 dimensional plane? [duplicate]

Older galaxies mostly tend the revolve forming a disk. Why are the stars not revolving around the center of the galaxy like a sphere instead similar to electron in an atom?
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### Stable Sides of Polygon Objects

I have a physics question for you. Let us say a polygon shaped object is stable on a side when the center of mass "falls" inside the base. Is it possible in 2D to build an object that is unstable on ...
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### Studying dynamic elasticity for finite deformations

this is not a question asking for help with a problem but one asking for help where to begin serious study of elasticity, particularly that applied to dynamic systems. Most textbooks about elasticity ...
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### Can energy conservation be derived from Newton's Laws?

Can the idea of energy conservation be derived from Newtons's laws? From inspection of his laws you can vaguely discern a relationship but I want to know of you can manipulate his laws to prove it. ...
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### All reference frame are inertial? Where is the flaw in reasoning?

This is my first post here. I have a line of thoughts which might be wrong but I couldn't find the error. Suppose we have a point mass subjected to an arbitrary force $F$. In the lab reference frame ...
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### Stress on a fixture [on hold]

How to determine the stress at point B and C and how can i calculate the maximal weight section A must be able to withstand?
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### What prevents the ball from falling down? [on hold]

A person runs on level ground as they hold on to a string. At the end of the string is a ball. The ball stays floating in the air. There is tension in the string pointing sideways, and gravity acts ...
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### 3D wave equation of a 3D object [on hold]

For an example I have to derive wave equation of a sphere, x^2 +y^2 + z^2 = r^2 and its solution (wave function). Boundary condition can be anything. I like to know about eigenvalue and its use at ...
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### Forces Create Angular Acceleration And “Straight” Acceleration - But How Much Of Each?

Let me set up the following problem for a rectangle floating in space: We know its dimensions. We know its mass. There's a force pushing it for a known amount of time - we know the angle & ...
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### On the Stability of Circular Orbits

Bertrand's Theorem characterizes the force laws that govern stable circular orbits. It states that the only force laws permissible are the Hooke's Potential and Inverse Square Law. The proof of the ...
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### Ball spontaneously rolling down hill [duplicate]

I'm trying to remember a problem in classical mechanics involving a special surface that allows a ball to roll to the top and lose all it's momentum in finite time. This leads to some interesting ...