Classical Definition and 1000 Threads

At the time Schwarzschild derived his solution (1915) he only had a version of the EFE that was not fully coordinate free, he used the equations in unimodular form, and therefore he could only consider the "outside of the star" part of the fully general covariant form we know now. So does a...

Homework Statement Greetings! This is an example problem at the end of Chapter 1 in Mechanics (Landau): A simple pendulum of mass m whose point of support oscillates horizontally in the plane of motion of the pendulum according to the law x=acos(\gamma t) . Find the Lagrangian...

The above is from another thread and I was rather intrigued as to what the posted spoke about. My schooling focused more on "how should my answers be for me to get maximum marks?" and as such, the phrase "rigorous classical education in the arts" seems quite vague to me. Would you guys be so...

I'm on pg 56 of Thorton's Classical Dynamics book and I see this: Imgur Link Two questions: 1) Where does the 2 go on the second to last equation. 2) Why v0^2 and not v0 on the integral?

Are there any mysteries yet unexplained in Classical Physics, Thermodynamics or Statistical Mechanics? Or do all the mysteries in physics come out of Modern Physics?

Here's a classical mechanics problem I'm having some trouble with: A particle of mass m moves on the positive x-axis under the influence of a force F=-K/x^2, where K is a positive constant. The particle is released from rest at x=R at time 0. Find the velocity as a function of x as it...

Homework Statement This is a problem from K & K, but I changed it very slightly. A light plane weighing 2,500 lb makes an emergency landing on a short runway. With its engine off, it lands on the runway at 120 ft/s. A hook on the plane snags a cable attached to a 250 lb sandbag and drags...

Hey guys, here is the question : A 5.4kg toboggan carrying 35kg of sand slides from rest down an icy 90m slope inclined at 30◦ below the horizontal. The sand leaks from the back of the toboggan at a rate of 2.3kgs−1. How long does it take the toboggan to reach the bottom of the slope? I...

Is Quantum Tunneling necessary to explain why The Sun keeps shining , due to it not being hot enough to provide the necessary energy for protons to collide?

Homework Statement I'm doing past a past exam (2003) and I'm stuck on the first exercise. Here it is: Consider a helix centered in the z-axis, of radius R and fixed step a, given in cylindrical coordinates by z=\frac{a\theta }{2 \pi }, r=R. A particle of mass m slides without rolling over the...

Cheers everybody, I've got a question about an equation in the famous paper "The Effect Of Retardation On The Interaction Of Two Electrons" by G. Breit. There on the first page, it is said, that a first guess for a two electron relativistic wave equation is made by constructing the...

What would be your go-to textbook for Classical Mechanics at the undergraduate level? It must also cover the Lagrangian and Hamiltonian formulation. My school uses "Analytical Mechanics" by Fowles & Cassiday but I find it not very complete and doesn't cover all topics. I've also read parts...

how we can differentiate classical and quantum fields?i searched everywher..but i did not get a satisfactory answer

Homework Statement A simple harmonic oscillator with mass m = 1/2 and k = 2 is initially at the point x = √3 when it is projected towards the origin with speed 2. Find the equation of motion describing x(t). Homework Equations x=Asin(ωt+θ) The Attempt at a Solution At t=0...

Classical Mechanics: Finding force, equilibrium points, turning points... Homework Statement The potential energy between two atoms in a molecule is U(x) = −1/x^6 +1/x^12 Assume that one of the atoms is very heavy and remains at the origin at rest, and the other (m = 1) is much less...

Could someone demonstrate to me how in Landau's Mechanics book, he gets from equation (16.5) tan θ = (v_0 sin θ_0) / (v_0 cos θ_0 + V) to equation (16.6) cos θ_0 = -(V/v_0) sin^2 θ ± cos θ √[1 - (V/v_0)^2 sin^2 θ] I am using the quadratic formula, and the first term on the right...

Homework Statement An Instrument carrying a projectile accidentally explodes at he top of its trajectory.The horizontal distance b/w the launch point and the point of explosion is L. The projectile breaks into 2 pieces which fly horizontally apart. The larger piece has three time the mass of...

Hi, I was wondering if someone could point me to a textbook or easy to read paper (or website) that briefly describes/proves the differences here. What I mean is if I do classical (continuous energies) statistical mechanics where my initial state is a volume (greater than or equal to h-bar)...

In quantum mechanics one can convert the wave function of one variable into the wave function of its conjugate pair (e.g., momentum and coordinate) using a Fourier transform. Now consider the classical case. Suppose there is a particle in a potential well with insufficient energy to escape...

Homework Statement I have a problem regarding to lagrangian. If L is a Lagrangian for a system of n degrees of freedom satisfying Lagrange's equations, show by direct substitution that L' = L + \frac{d F(q_1,...,q_n,t)}{d t} also satisfies Lagrange's equations where F is any ARBITRARY BUT...

i learned that we have to consider quantum effects at low temperatures and classical effects at high temperatures but i do not the physics behind it can anyone explain it for me? thanks in advance :)

i need someone to explain me the aberration of light , i tried to read i from my book its a bit more complicated than i thought i mean when we move the microcope we make a tilt what do you mean by that? all in all i didnt understand this concept and i need a really clear explanation especially...

This has been nagging me in the background of my mind for many years and I've decided to get it sorted. I note that I'm not sure if this should be in the classical or quantum forum. I have heard it mentioned by many and often when referring to the inherent uncertainty when measuring...

When we setup the Schrodinger equation for the hydrogen atom we use the classical electric potential. It seems that we would need a new potential instead of mixing QM and classical. Is this just a very good approximation or is there something subtle.

Trying to get the idea behind this, but it's kind of new thinking all this rotational dynamics. The classical example of conservation of angular momentum is when a ballerina pulls in her arms as she spins to spin faster. The angular momentum theorem tells us: I1*α1 = I2*α2 So as she decreases...

I've just seen this article: http://www.newscientist.com/article/dn21235-entangled-diamonds-blur-quantumclassical-divide.html Was published yesterday (or today?). Makes interesting news.

I've heard it said that 'we don't really understand turbulence', and that it is one of the biggest outstanding problems in classical physics right now. (Or at least Feynman thought so back in his day) But what is there to understand about turbulence and why don't we understand it? I thought...

I do not know but I do not know if Ampers law is valid for short conductors passing through a loop. I did integrate and my integral was different from the expected I*U. The law seems to be valid only when long conductors pass through a loop but not short ones. Can anyone explain what am missing?

I like your explanation, and I agree. However, why does it not work for the case of gravity? To be more specific, I'm talking about the mainstream classical justification for the equivalence principle as it applies to active gravitational mass. Let me give an analogy that applies to the OPs...

Hello. I'm trying to understand why, in terms of Maxwell's Equations, the ratio of the number of turns in a transformer converts an input voltage to an output voltage. EE explanations only seem to go as deep as this article: http://en.wikipedia.org/wiki/Transformer#Basic_principles They state...

I'm learning mechanics right now via an extension course. In the absence of an "on-demand" teacher I've found multiple textbooks and online resources to be useful. When I studied calculus, Paul's online calculus notes (http://tutorial.math.lamar.edu/Classes/CalcII/CalcII.aspx) were a great...

Homework Statement A mass, m, is attached to a support by a spring with spring constant, k. The mass is hanging down from the spring, so there is a gravitational force on the mass as well. Neglect any resistive or frictional force. The support is then oscillated with an amplitude of A and...

Hey guys, First time posting. I was thinking of starting an extra credit paper for my Physics 1A course, and was wondering if anybody could think of any noteworthy and recent applications of classical mechanics that I could do some research on. I was thinking of maybe pursuing dark matter as...

Hi, I'm a bit confused wit the concept Configuration Space. First, the professor defined generalised coordinates as such: U got a system of n particles, each particle has 3 coordinates(x,y,z), so u got 3n degrees of freedom. If the system has k holonomic constraints, u got 3n-k degrees...

This is really simple but I can't figure it out. I was on a bus when I thought of this: Say I'm sitting in the back of a bus which is traveling on a flat surface, and accelerating with a constant acceleration (forward). Now I get up from my seat in the back and make my way to the front of the...

Has there been work done exploring the possible connection between chaotic systems and quantum mechanics? Chaos basically tells us that an infinitesimal change in initial conditions, given enough time, will lead to complete different solutions - another way of stating that is over enough...

Homework Statement Set up the equations of motion for the system shown in Fig. 4.16. The relaxed lengths of the two springs are l1, l2 . Separate the problem into two problems, one involving the motion of the center of mass, and the other involving the "internal motion" described by the two...

How the Deutsch's algorithm outperforms a classical algorithm? In both algorithms we need two particles (two bits and two qubits). In the quantum case the two qubits are processed by the FCNOT gate simultaneously but it's equivalent to two classical "black boxes". So if we take two classical...

I am interested to know everyones favourite piece of classical music! I am a hopeless musician, but i love listening to classical music whilst i do mathematics, its like transcending to another plane of existence.

First of all, I haven't the slightest idea how a quantum computer actually works but I understand that it is theoretically possible to make them and they could, in theory, be used to compute things that a classical computer would take too long to compute. (i.e. large combinatorial problems like...

in the literature, people are talking about 'quantum systems without a classical limit' could anyone give me an example?

Will taking a course is continuum mechanics give me the same background as in classical mechanics or would I need to take both separately? Can anyone explain the difference if there is one between classical mechanic vs continuum mechanics in simple nontechnical terms.

Homework Statement Consider the bead threaded on a cicular hoop of example 7.6 (pg 260), working in a frame that rotates with the hoop. find the equation of motion of the bead, and check that your result agrees with eq 7. 69. Using a free body diagram explain the result 7.71 for...

Not sure whether to put this in the QM forum or the classical forum, you'll see why-- I was thinking about the http://grad.physics.sunysb.edu/~amarch/ version of the double slit experiment, in which the information about which slit the particle went through is obtained in a somewhat unusual...

Hello PF group. Long time reader, first time poster. Can someone please make some recommendations for a good classical physics textbook, particularity suited to self-learning classical physics? I'd also like the recommendation to not be calculus based. My preferences are for something...

Homework Statement A particle of mass "m" whose motion start with downard velocity V0 in a constant gravitational field. The drag force is quadratic and proportional to kmv2. What is the distance s through which the particle falls in accelerating from v0 to v1. Give your expression for s in...

Homework Statement show that y=ex-vt)7/8 Homework Equations d2y/dt2= d2y/dx2 The Attempt at a Solution i don't understand how they solve this. in the book they have dy/dt=ezdz/dt=-7/8vez(x-vt)-1/8 I thought it would be -7/8veex-vt)7/8 not sure what they did any. thanks

After studying both areas of classical and quantum physics in some depth, I've reached the conclusion classical physics is more elegant and ingenious than quantum physics. Newton's law of gravitation is elegant because its sheer simplicity allows us to map the trajectory of satellites...

When does quantum "take over" classical? There's seems to be a lot of information about how relativity "takes over" classical mechanics when certain speeds are reached, like at a certain % of speed of light, etc. I haven't found much information regarding when quantum mechanics takes over for...

Can someone explain to me how an atom can absorb the energy of an incident photon without being ionised? What is the photon energy transformed into and how is it transferred between the photon and the atom (what part of the atom absorbs the energy?). I can't find anything helpful online - the...