Principle Definition and 1000 Threads

I am reading Ethan D. Bloch's book: The Real Numbers and Real Analysis ... I am currently focused on Chapter 1: Construction of the Real Numbers ... I need help/clarification with an aspect of Theorem 1.2.10 ... Theorem 1.2.10 reads as follows: Towards the end (second last line) of the...

So around 44:00, Susskind begins his argument. He put a variety of items into a region of space, and the added a minimal shell of material surrounding the items, then squeezed that material to form a black hole around the item. Then he said that the amount of original information cannot be...

I'm wondering how does speedometer work. To be specific let's talk about car speedometer. I googled it and found out that there are different kind of speedometers, but not quite understood it's working principle. My question is not about how it shows us speed (Mechanically with arrow or...

Well, i came across the so-called both the forms of the uncertainty principle of Quantum Mechanics: the position-momentum form and the energy-time form; but i am not satisfied in one way. Here the trio: position, momentum and energy, all of them have their own operators, but time does not have...

Let me preface this post by saying that I only have a very cursory understanding of general relativity. I happen to know that if we assume the cosmological principle, then the hypersurface ##\Sigma_t## of the spacetime manifold ##M##, for any positive ##t##, is either a 3-sphere, a...

The images have been taken from the section : Relativity according to Galileo and Newton, page no.66, special relativity , A.P.French,1968What I understood is: According to the first paragraph, Laws of transformation are needed so that a theory which describes a phenomenon w.r.t. one reference...

An isolated mechanical system can be represented by a point in a high-dimensional configuration space. This point evolves along a line. The variational principle of Jacobi says that, among many imagined trajectories between two points, only the SHORTEST is real and is associated with situations...

Mach, Newton and others observed that centrifugal forces appear in a object when it rotates in relation to the stars. Einstein was convinced by this and tried, unsuccessfully as far as I understand, to incorporate what he called Mach’s Principle into General Relativity. From Wikipedia -”Mach’s...

To my understanding(correct me if I am wrong), one consequence of the Heisenberg Uncertainty Principle is that energy levels can fluctuate by some amount, e, for a short time, t. As long as e x t does not exceed h/4pi (where h= Planck's constant). My quarry is that what are the units for the...

I'm reading a book on vortex methods and I came across the above mentioned terms, however, I don't understand what they mean in mathematical terms. The book seems to be quite valuable with its content and therefore I would like to understand what the author is trying to say using the above...

Homework Statement https://holland.pk/uptow/i4/1ca04ddf7c25f6c63e307720c34a4ff3.png Homework Equations First principle of thermodynamics: E=q+w The Attempt at a Solution E=q+w=-17+21=4kJ>0 ∴Endothermic (absorb heat from surrounding) (a) false (from surrounding to the system) (b) false (does...

For finding the inverse of a matrix A, we convert the expression A = I A (where I is identity matrix), such that we get I = B A ( here B is inverse of matrix A) by employing elementary row or column operations. But why do these operations work? Why does changing elements of a complete row by...

We have to find a movie that has 3 good examples and 3 bad examples of this principle. We were thinking about doing Finding Nemo however we can't think of 3 bad ones and we are worried that our physics teacher might reject it since it is not a "serious" movie. Any ideas?

Homework Statement Hi, in my high school physics class we have to teach (part of) a lesson, mine being archimedes principle, and we have to make a demonstration of our topic. My idea was to show how you can calculate the buoyant force on a immersed object with the weight of the water it...

When Dave borrowed $3100 at 15% per three years, the principle was? Do I use I = prt? If so, the set up is 3100 = p(0.15)(3), right?

Hello, I tried looking this up a lot and just could not find it. For four bar linkage, Klein's construction is used to find velocity and acceleration of piston and connecting rod. Here is a link for the procedure of the same...

Hello,I am reading the link http://math.mit.edu/~jspeck/18.152_Fall2011/Lecture%20notes/18152%20lecture%20notes%20-%204.pdfSays : w_t-D w_{xx}=f with f<0w at \bar{Q}_T has its maximum in \partial_p {Q}_T. If w is strictly negative at \partial_p {Q}_T then also is strictly negative in...

Hello all, I have a few small questions, related to the pigeonhole principle, which should be the guiding line for the solution. I had more, but solved the easier ones. 1) Prove that each series of 10 integer numbers has a sub-series of following numbers such that the sum of the sub-series is...

I have just come across the following on the Astronomy Picture of the Day. https://apod.nasa.gov/apod/ap170423.html Here is a quote that I would like to learn more about. The Holographic Principle, yet unproven, states that there is a maximum amount of information content held by regions...

Homework Statement A uniform horizontal rod of mass 4 kg and length 500 mm, is hinged at the left hand side and supported at rest by a chain (S) attached 10 cm from the hinge. Calculate the magnitude and direction of the reaction force on the rod at the hinge. State the principle you have...

Homework Statement A horizontal stream of air is blown just above the open end of the hares apparatus with an initial speed "V". The density of air is 1.2 kgm-3.Then the water column rises to 6 cm in the respective limb.Density of water is 103 kgm-3 Using Bernoulli`s principle find "V"...

If I have this right, when we have exact certainty of a particle's momentum, the bounds of this particle's location cannot be determined. Now there are some who believe in a universe of finite volume and so this particle has to be within this volume. So there seems to be a contradiction. Does...

The last chapter of most introductory textbooks on STATICS introduces VIRTUAL WORK. It is rarely taught (I studied the syllabi of colleagues). I understand the Principle of Virtual Work, having researched and studied the Calculus of Variations, Hamilton's Principle, the Lagrangian and related...

I am now taking optics class at my school. Fermat principle can be applied on mirror of course. Then what about Concave mirror? According to the calculus of variation. the optimized path(actual path of the light) should be the shortest path. but in the concave mirror case, it goes through the...

https://www.sciencedaily.com/releases/2017/03/170322143233.htmDate: March 22, 2017 Source: ICFO-The Institute of Photonic Sciences Summary: Researchers report the discovery of a new technique that could drastically improve the sensitivity of instruments such as magnetic resonance imagers (MRIs)...

In the classical definition, velocity is the time derivative of the particles position curve (trajectory). The Uncertainty principle restricts the particles velocity from ever being zero. Doesn't this imply that a particles path is restricted to paths that do not have a zero time derivative at...

<Moved from the homework section> 1. Homework Statement I have read several chapters of De Brogile's article "the theory of quanta".The motion of a particle could be analogious to a ray in general optics.This is an analogy between Maupertui's principle and fermat's principle. How to use this...

"As all good textbooks of quantum mechanics have to emphasize and clarify in one way or another, it is critically important that one avoids the assumption that even before the measurement, any of the quantities that may be observed later already have some objective, particular values." Imagine...

Hi pf, Please help me, the more I read about HUP, the more discrepancies I find between different sources. I found a good article that Zapper made on HUP (https://www.physicsforums.com/insights/misconception-of-the-heisenberg-uncertainty-principle/). My confusion is about the way it is...

I don't know if anyone remembers me. I'm not a physicist but I tend to do pretty well at understanding some of the basic principles of classical physics, and that's recently created food for thought on my part.There's a message board I've found that is devoted primarily to debunking popular...

Hi community, I have a question about the Bernoulli principle. From statistical mechanics the pressure in the ideal gas is independent of velocity. But in the case of the flow of an ideal gas in a channel, the pressure depends on the velocity. Where can I clarify this misunderstanding...

In lagrangian variation we are trying to minimize the action S = ∫t2t1 L dt. Consider a simple case of free particle. Imagine In a world that everyone one only knows how to solve ODE, Using euler lagrange equation, one has d2x/dt2 = 0 , give that we know the initial position of particle in the...

Suppose that somehow we could artificially bypass Pauli exclusion principle, and make electrons or any fermions for that matter occupy more than one state at the same time? What consequences in nature will we see? what phenomenons will occur? Suppose this mechanism for bypassing is limited in...

I was wondering - if you had a container of water and you push a hollow object that is buoyant to the bottom so that it is completely immersed - the whole container will be heavier because of water being displaced up in the container. Now if you release your hand or whatever you use to hold the...

1 - Huygens-Fresnel principle states that every point in a light wave is itself a wave source, 2 - light is made of photons, 3 - photons have a wavelength, they are QM objects. Hence my question : are photons the actual wave sources in Huygens-Fresnel principle ? Or are those two...

So the Holographic Principle says that our 3 dimensonal world is encoded in the 2d surface of the cosmological horizon. What about the remaining dimensions? Are they there in the regular 3space or are they also encoded?

Take a U-shaped piece of pipe, standing upwards. Fill the bottom part with liquid and leave the 'prongs' open. Now slam a parcel of liquid into one end at high speed. The other end will experience some momentum exchange and go pushed upwards. Now take the same test case and add some piping...

Homework Statement I learned how to deriving Maupertuis's principle from Hamilton's principle under conservative energy condition and feel this interesting. But when trying to derive a particle's behavior in gravitivity field,stuck... The direction of grativity is along ##x## axis,the particle...

So if someone is in an elevator moving up at g in outer space, vs someone in an elevator in a uniform gravitational field of g, there is no way telling whether one is in an elevator in outer space or resting on earth. But what is the big insight about this? Isn't this true classically as well...

At the moment I'm working with the https://en.wikipedia.org/wiki/Schwinger's_quantum_action_principle']quantum[/PLAIN] action principle of J. Schwinger. For this I read several paper and books (like: Quantum kinematics and dynamics by J. Schwinger, Schwinger's Quantum action principle by K.A...

Hey everyone, I'm writing a paper about major events/turning points and wanted to cite a scientific principle. Does anyone know if there is a physics (or any scientific) principal that refers to major turning points or the specific steps that lead to a certain outcome? Thanks so much!

Homework Statement During class we did a lab testing Le Chatelier's Principle where we took FeSCN-(aq) and added water in order to dilute it to a lighter colour (red to orange) and to make a stock solution. We then divided the stock solution into several test tubes. In one of them we added...

Homework Statement Archimedes, prove your stuff. A royal crown (cola?) of pure gold is suspended in air by a thread and the tension in the thread is of magnitude T. When the crown is totally immersed in water, the magnitude of the tension in the thread is 0.872T. A) sketch a second law force...

Homework Statement One way of moving a large undersea rock or mooring is to fasten a closed, empty oil drum to the rock while at low tide. As the tide comes in the drum is drawn down into the water increasing the buoyant foce acting on the system of the rock and drum. Suppose a cylindrical drum...

Hi, I have an issue with a question I am trying to answer and I don't seem to be getting the correct answer... Question A 950kg cylindrical can buoy floats vertically in sea water, the diameter of the buoy is 0.860m. Calculate the additional distance the buoy will sink when a 70kg man stands...

The Church-Turing-Deutsch Principle states that any physical law can be computed. This is a strong statement which many physicists assume without justification to be true at face value. However, I have not seen proof of the CTD principle being true. From what I understand David Deutsch...

How does one prove the Church-Turing-Deutsch Principle? The principle states that a universal computing device can simulate every physical process. Not sure where to post this, as it seems like a pertinent question in proving the simulated universe thesis right or wrong along with possible...

Homework Statement [/B] A rectangular object has a width of 40 meters, height of 15 meters, and length of 2 meters. It floats consistently when 3 meters of its height is below the surface of the water. 1. Find the volume of the displaced water. 2. How much is the buoyant force on the object...

Tidal Forces: "It arises because the gravitational force exerted by one body on another is not constant across it". which implicitly implies that the acceleration is not constant on that body. Equivalence Principle: "weightlessness sensation occurs when one free falls in gravity" - which...

What is the explanation for the case that fermion's can't occupy the same quantum state? Is there some logic behind this or is it just observation?