Principle Definition and 1000 Threads

Homework Statement Hi! The problem states: Water through a certain sprinkler system flows trhough a level hose connected to a nozzle which is directed directly upwards. The water leaves the nozzle and shoots to a height, h, before falling back down again into a pool. The hose is connected to...

Homework Statement A 0.2 lb gear is released from rest in the position shown (Okay so this essentially a circular gear in the groves on an adjacent wall that is also circular. Think perpendicular circles with different radii. The gear is a circle, and the gear teeth are in a circular...

Hello everyone,can anyone help me to understand the phase congruency principle. I have read that,in image processing if we reconstruct an image using its phase only,we can get obtain edges and lines and this is because of phase congruency principle. I am searching more about phase...

Homework Statement This is problem 6.3 in Taylor’s Classical Mechanics. It is in context of the calculus of variations. Consider a ray of light traveling in a vacuum from point P1to P2 by way of the point Q on a plane mirror, as in Figure 6.8. Show that Fermat's principle implies that, on the...

[SIZE="4"]Definition/Summary This is a derivation of the Uncertainty Principle based on the properties of non-commuting Hermitian operators. [SIZE="4"]Equations \langle (\Delta A)^2 \rangle \langle (\Delta B)^2 \rangle \geq \frac{1}{4} |\langle [A,B] \rangle | ^2 \langle (\Delta...

I am unable understand this Integral, what does it actually saying? What does that "δ" means here? I haven't learned Calculus of variations, explain me with diagrams with possible.

The expression gives time taken to reach a a distance ds in a medium. The expression has the dimension of time, But my question is how come the denominator is (c/n)? why it can't be (cn)? explain me.

Homework Statement Finding the time period of a conical pendulum by D'Alembert's principle. The string is of a constant length and all dissipations are to be ignored. Homework Equations The time period of a conical pendulum is 2\pi \sqrt{\frac{r}{g\tan\theta}}. I need to arrive at this result...

Homework Statement (see attatchment) We know masses M and m, and I am trying to describe the downward speed of m in terms of the hight from the ground. There is no friction Homework Equations \sum \text{F} = ma W_{\text{total}} = \Delta K = \int \text{F} \cdot d\text{s} The Attempt at...

I'm getting a rough idea of the holographic principle relating the shannon entropy of a boundary surface to the thermodynamic entropy contained within the bounded volume. So far as I understand the primary claim is that the total information needed to describe the entirety of the internal...

These questions applies to both spatially homogenous cosmological models, and multidimensional Kaluza-Klein theories: Suppose we have a manifold M, of dimension m, for which there is a transitive group of isometries acting on some n-dimensional homogeneous subspace N of M. Thus there exists a...

Hi, I'm doing further maths and I would like to study maths at university. I have been asked to read a number of books to put on my personal statement, and as I am finding it difficult coming to terms with the fact that mechanics is taught as maths and not physics, a maths don at Oxford...

When it actually 'equal to' in uncertainty principle? For example under what conditions: ΔxΔt = h/4pi

Hey guys, I don't know if here is the right section for this question but anyway. So I was looking for the proof or derivation of the Fermat's principle and all I got was the Huygens–Fresnel principle. However, neither could I understand how the Huygens–Fresnel principle derives the Fermat's...

In a new paper http://lanl.arxiv.org/abs/1407.0989 Haggar and Rovelli offer a new solution to the black-hole information paradox, by proposing a time-symmetric scenario in which black hole tunnels into a white hole. I think the main problem with this proposal is violation of the second law...

For the infinite square well in one-dimension the wavefunctions have the form Acos(kx) where k is the wavenumber which is proportional to momentum. Now due to H.U.P. if Δx is fixed as the infinite well size we can't know the exact momentum. I presume this is because the wavefunction exists as a...

Homework Statement A 100g object having a density less than that of water is placed into a beaker half full of water. The beaker is then placed on a triple beam balance. Would be measured weight be equal to, greater than, or less than the weights of the water, the beaker, and the object added...

Pauli's Principle says: "The wavefunction of two identical fermions must be totally antisymmetric". I know that, for a antisymmetric wavefunction, (-1)^L*(-1)^{S+1}*(-1)^{I+1}=-1 "totally antisymmetric" means this relation or it means that these 3 relations: (-1)^L=-1 and (-1)^{S+1}=-1...

Homework Statement To verify her suspicion that a rock specimen is hollow, a geologist weighs the specimen in air and in water. She finds that the specimen weighs twice as much in air as it does in water. The density of the solid part of the specimen is 5.0 x 10^3 kg/m3. What fraction of the...

Hey! :o I am looking at the proof of the strong maximum principle: If a function $u$ satisfies the Laplace's equation at the open space $D$ and is continuous at the boundary $\partial{D}$ and achieves its maximum at $\partial{D}$ and at a point of $D$ then the function is a constant. which is...

I have been reading and would be interested in feedback to the comments that I make, below. One of the points made in this paper is that the interpretation of the uncertainty relation needs to be re-examined in its relation to the viability of having simultaneous measurements of A & B. For...

Hi all, Here is the derivation of kinetic energy from Work: W = ∫Fds From the second law of motion F = dp/dt, which is equal to mdv/dt, so: W = m∫dvdx/dt which = m∫dv x v because dx/dt = v Therefore W = 1/2mv2, when integrated. However from simple algebra derivation, W = Δ1/2mv2...

A test question I was asked earlier in the year has been hanging around in the back of my mind: "If a radio is moved 3x further away from you, how is its loudness affected?" To answer this question one needs to know what determines the loudness of sound. What determines the loudness of...

I have a question: can the mechanism behind Pauli's exclusion principle be considered a fundamental force, like gravitational, electromagnetic, nuclear weak or strong? Why? Thx.

Homework Statement Five cards numbered 1 to 5 are shuffled and placed face down on a table. Two of the cards are picked at random. [Hint: find all of the possible outcomes of this experiment which form the sample space S and use the Equally Likely Principle.] Find the probability of the...

Homework Statement A wooden block with mass 1.25 kg is hit by a bullet with mass 5.00 g and the speed vi according to the figure. The bullet sticks in the block and together they go up to the maximum height of 22.0 cm. Calculate the initial speed of the bullet. Homework Equations...

I was watching a YouTube video about Heisenberg's uncertainty principle and was wondering if it only works for position and momentum or does it work for any other two measurable quantities?

I know this may sound strange, given that we cannot really work out where in space a photon is because it cannot be completely stopped. But here's a thought. Let us assume that a photon has been emitted in vacuum going in a straight line. At any given moment in time, this photon will have...

Hi. I am reading a book entitled "Atom-Photon interactions" by Claude Cohen-Tannoudji, et al. There is a symbol which looks like \mathscr{P}. The authors state that this symbol stands for the principle part. e.g. \hat{\Delta}_b(E)=\frac{1}{2\pi} \mathscr{P} \int dE'...

Hello, i'm solving some quite simple problems using the uncertainty principle, but I don't have access to the solutions and I really don't have a feel for what a 'sensible' answer is... When finding the minimum uncertainty in velocity, I end up with things greater than the speed of light, so I...

Hello, I need some help understanding Bernoulli's principle, flow rate, velocity and pressure. I understand that when the diameter of a pipe decreases, the velocity will increase and the pressure will decrease. But I am having a hard time applying this to a practical application. For...

To which type of Fundamental forces below the Pauli's exclusion belong? Strong nuclear forces Coulomb forces Weak nuclear forces Gravitational forces

Uncertainty principle -- Nature of observer About the fact that electrons have a determined position only after having been observed/measured, I don't understand how they make the difference between being watched by an eye/instrument or any non-measuring object just sitting there.

Why is it that Susskind in describing the holographic principle - why is it that he considers a quantized universe?

Hey guys, I would just like some confirmation that I got this question correct. Homework Statement For the stress block shown in Figure 3a, using the stress equations; a) Calculate the stresses sigmax' sigmay' and taux'y' on a stress block rotated 15° clockwise from the x-y axes...

Homework Statement When Θ=0, the assembly is held at rest, and the torsional spring is untwisted. If the assembly is released and falls downward, determine its angular velocity at the instant Θ=90°. Rod AB has a mass of 6kg, and disk has a mass of 9kg. Rod is 450mm and disk has a radius of...

How does Fermat's principle of least time (that if light goes from one point to another, any small deviation in the path will result in a path that takes the same time on the first order) follow from Huygen's wave principle? Everyone always says that Fermat's principle can be derived from...

I now have a general understanding of relativity but it threw up a few issues. I understand that there are no 'fixed' points of reference in the universe, which of course begs the question as to why inertia exists. The way I imagine it is if I am the only matter in the universe, then why should...

Homework Statement A swimming pool with 5 M length and 4 M width.A big layer of ice floats on the surface of the pool and above the layer of ice a rock with 40 KG mass and 5 R.D.,If the ice is melted and the rock fall, calculate the change in the height of water in the pool final answer...

..Quick rundown on 0-th principle of thermodynamics in relation to GR and QM. Some insight on LQC-(slide to 19:07) using quantum state 'of' time in a semi-classical approximation. Fun way to think of things.^^

Recently, I was reading about Hawking Radiation in A Brief History of Time. It says that at no point can all the fields be zero and so there's nothing like empty space(quantum fluctuation etc.). Now, the reason mentioned was that virtual(force-carrier) particles cannot have both a precise rate...

Hi, all there are equation in the pic but I can't understand them. I know work-energy principle which is W= F * X (work equals force times way) but I think they are special forms. What concepts and topics should I study to understand them?

So I understand the Superposition principle doesn't apply to non-linear systems. I want students to understand (in high school physics...which I will be teaching in about a year) that the superposition principle essentially says things add. So I wanted to come up with some examples when this...

Can one deduce from Pauli's exclusion principle (through the Slater Determinant) that two electrons with different spins in the same energy level, can't have the same position?

In an explanation to distinguish the Heisenberg Uncertainty Principle from the Observer Effect, on p. 89 of "Quantum Computation and Quantum Information", Nielsen and Chuang start by writing: "The correct interpretation of the uncertainty principle is that if we prepare a large number of...

It is taught that the classical treatment of the diatomic atom would give a heat capacity of $7/2$ due to 7 degrees of freedom, (three translational momentum, two rotational momentum, on vibration momentum and on vibration position). This is based on the Hamiltonian looking like: $$ H =...

Homework Statement http://postimg.org/image/m9wtlg5ah/ taking T1 for example why does the disk have no translational kinetic energy component? And why does the friction do no work? Homework Equations Kinetic energy of a rigid body in planar motion T = ##\frac{1}{2}m{v_G}^2...

Homework Statement A cylindrical log of uniform density and radius R=30.0cm floats so that the vertical distance from the water line to the top of the log is d = 12.0cm. What is the density of the log? Homework Equations Fbouyant=Wwaterdisplaced ρwater * V displaced water = ρlog *...

Hello, As written, I am wondering if the causality principle gets violated in QM. Do virtual particles violate the causality principles? Do instantaneous events violate the causality principle? Thank you in advance.

For the ground state of harmonic oscillator i have \Delta p \Delta x =\frac{\hbar}{2} why if i do \frac{1}{F} \Delta p \Delta x \cdot F =\frac{\hbar}{2} \Delta t \Delta E = \frac{\hbar}{2} \Delta E = \frac{\hbar}{2} \frac{1}{\Delta t} \Delta E = \frac{\hbar}{2} f but my answer...