Principle Definition and 1000 Threads

This is a question I've had for some time now. Why is the exchange interaction not considered a force, like the other 4 fundamental forces? When reading solid-state physics texts, for example, I come across explanations of this kind: the atoms cannot get too close together because of the...

Heisenberg's uncertainty principle asserts a fundamental limit to the precision with which certain pairs of physical properties of a particle, such as position and momentum, can be known simultaneously. The more you know about one, the less you know about the other. Why does the following...

Superposition principle? How to algebraically add up two equations?? How do you add up (λ (√3)) / (4pi(ε naught)R) (√3/2 i hat - 1/2 j hat) + (λ (√3)) / (4pi(ε naught)R) (√3/2 i hat + 1/2 j hat)? the 1/2 j hat cancels out right? but what do i do with everything else?

Hi, So I came across this article on the internet, and it was about the Equivalence Principle. So I were interested and read it all, and in the article it said that the EP might be only approximately true. What interested me more about the article was it said that any theory of quantum...

Hi all, It is really a history question. I read that Galileu developed the concept of inertia, but today I knew it from Newton's 1st law. So my question is: Both of them arrived at the idea independently? Was Newton aware about Galileu's work and used the law because it is the basis for his...

I'm trying to understand the uncertainty principle. ΔxΔp >= h/4∏ from my understanding of the concept, its not possible to know the value of the position and the momentum simultaneously. yet the problems that i see floating around on the internet seem to just plug in values for mass and...

I've been giving some thought to the new scientist article about the equivalence principle. What initially seems like a very simple issue is remarkably tantalising. (please note- I'm not a physicist so this may be quite stupid) This led me on a little to the question of gravity and direction...

What’s your understanding of the principle of equivalence? In the literature, I find two meanings: (1) Gravitational mass is numerically equal to inertial “mass.” (This is a postulate.) (2) A mass at rest in a frame is equivalent to being in a “gravitational field” in an accelerated frame...

It is said that if there is a change in pressure in an equilibrium state, the chemical reactions that diminish the number of molecules will be favorised. Therefore, there will be less molecules, so the pressure will decrease to reach equilibrium again. However, since the kinetic energy of the...

A photon is considered as a quantum particle, right? However since we know the speed of a photon(speed of light) and hence can predict its position, isn't it violating the Heisenberg Uncertainty Principle? Where am I going wrong? Is it false to believe that a photon is a quantum particle?

hi guys I want to know what is the Franck-Condon principle?... please in details thanks for all

Homework Statement I'm not sure on the principles of moments Homework Equations The Attempt at a Solution Is it just that moments are a turning force?

This question may have been posted before, but I didn't have much luck finding it. We can't know the momentum and position of a particle at the same time, but if one were to entangle two particles (I.e. photons), wouldn't it be possible to measure one quality on each and thus deduce both the...

Hi does anyone know how bogulobov transformations are related to the Heisenberg uncertainty principle?

A geode is a hollow rock with a solid shell and an air-filled interior. Suppose a particular geode weighs twice as much in air as it does when completely submerged in water. If the density of the solid part of the geode is 3100 km/m^3 , what fraction of the geode's volume is hollow? The...

I have just began my journey in General Theory of relativity through the book of Weinberg-Gravitation and cosmology principles and applications of the general theory of relativity I don't know if this topic is just a repeat of an older one, if it is please let me know the link to it... I...

[b]1. Somebody help explain how to do this for me, am not looking answer, an explanation so i can solve it would be great. A space vehicle traveling at a velocity of 7000km/h separates into two sections of mass 1100kg and 200kg. the two parts continue moving in the same direction with the...

View the attached picture that is the problem that I need help with.

Question: Suppose a person weighing 530 Newtons is floating in a salt lake (concentration of 20% NaCl) with a specific gravity of 1.148. How much less of the person's body would be in the salt water as compared to if he were floating in ordinary water (w/ density 1.00g/cm^3)? Comment: One...

Homework Statement The problems are attached in the photo below (or at least I'm hoping they are, doing this from my Ipad makes this somewhat diffcult) Homework Equations Not really an equation, but the Principle of Superposition states that the amplitude of two interfering waves are added...

We say that the laws of nature (e.g. Newton's Laws, relativity, ...) must be confirmed and must be checked for invariance (e.g Lorentz, gauge, ...). Yet many of these laws may be directly derived from the principle of least action. Why do we not consider the principle of least action a law...

In some experiments like Heisenberg's microscope and Davisson–Germer experiment,we see that by using light to understand the actual path of electrons,the electrons are disturbed and so the result is changed(in the second case,the interference pattern is replaced by the distribution of classical...

According to this article, scientists were able to bypass the Heisenberg Uncertainty Principle, creating relative certainty in measurement of both position and momentum. Any thoughts, objections, comments?

http://www.livescience.com/18567-wac...principle.html are these once again bold claims? they are saying the uncertainty principle isn't just in measurement but in the very nature of the quantum. It seems to be bold claims and not reperated anywhere on any other sites and certainly doesn't...

Greetings, This is more of a question about the philosophy of science than physics. In fact, it's just a vocabulary question, so should have a one-word or one-phrase answer (similar to "Occam's razor"), if there is one. Is there a word or phrase for the following scientific principle (my...

Does a uniformly accelerated charged particle radiate em waves? The equivalence principle says that a particle in uniform acceleration is equivalent to a particle at rest in a gravitational field. A particle at rest in a gravitational field is clearly not going to radiate em waves therefore by...

I'm reading a book wherein the Earth's rotation is supposedly slowing down. The author claims that a ball thrown in the air would fall faster and harder... But if the rotation slows, wouldn't the equivalence principle say that the smaller acceleration could also be interpreted as a smaller force...

has anyone worked on using the spin of certain sister pairs of subatomic particles as digital communication that is that to have a device that spins one sister particle one way or another, that spins its sister particle in a receiver on the other side of the world or universe where a sensors...

As my knowledge of an electric field strength becomes more precise, what physical quantity becomes correspondingly less precisely known?

Hey! I have got some question for you. Decide if you can choose seven tops of the regular 19-gon and four of them are tops of trapezoid. (I think - Pigeonhole principle, but how?)

Consider two hermitian operators A and B. Imagine a system is in state |\psi\rangle ,then we have: \langle \psi|[A,B]|\psi\rangle=\langle \psi|AB-BA|\psi\rangle=B^{\dagger}A^{\dagger}|\psi\rangle-BA|\psi\rangle=BA|\psi\rangle-BA|\psi\rangle=0 This just seems a little strange,for example...

To make the confusions both concise and explicit, I will put down some incorrect calculations, and ask for corrections Take the Lagrangian KE - PE = T - V Action = S=∫ L dt (with given limits) Principle of least action: δS= 0: S(t1)-S(t2) =0 if t1-t2 is small (using the (.) as function...

It is stated that in the holographic principle (e.g., in http://en.wikipedia.org/wiki/Holographic_principle) that the the description of a volume of space is encoded on a light-like boundary to the region. But with respect to which position in the volume? In a black hole, it is clear, because...

Homework Statement Hi there, I'm kinda confused about these two problems. An equilibrium mixture of NO(g), O2 (g) and NO2 (g) is allowed to expand from 1.0 to 2.0 L at a constant temperature. Given that 2 NO (g) + O2 (g) ---> 2 NO2 (g) which of the following statements is correct? (A)...

The principle of induction states that: Suppose\ that\ P(n)\ is\ a\ statement\ involving\ a\ general\ positive\ integer\ n.\ Then\ P(n)\ is\ true\ for\ all\ positive\ integers\ 1,2,3,...\ if\ (i)\ P(1)\ is\ true,\ and (ii)\ P(k) \rightarrow P(k+1)\ for\ all\ positive\ integers\ k. I found...

Say you have a particle in a one-dimensional box of length L. The particle can only have momentum values of the form p_{n} = \frac{nh}{2L} according to the De Broglie standing wave condition. Now say I don't measure the position of the particle, but I know for certain that it is in the box...

Homework Statement Two very large open tanks A and F (the figure (Figure 1) ) contain the same liquid. A horizontal pipe BCD, having a constriction at C and open to the air at D, leads out of the bottom of tank A, and a vertical pipe E opens into the constriction at C and dips into the liquid...

Hello everyone, I want to start by saying this is my first official visit to the forum, however I have been using the forum for several years to help me through my classes, and I owe a big thanks to all who are involved for getting me through some tough times! Now, on to my question...

Hey all, I have what I think (hope) is a relatively quick pair of questions regarding entanglement of fermions and bosons. First, am I right in saying that if two fermions are in the same position-state, they will necessarily be entangled? My reasoning here is just that if their...

hi pf, i am so confused with this energy time uncertainty principle. Somewhere i find that this means law of conservation of energy can be violated for a while and somewhere i find this still being a mystery? please help me out.

Are chromium and copper the only exceptions to the Aufbau Principle? If not, what are all the exceptions? Is there a list of some sort that would state all the exceptions to the Aufbau Principle? Thank you.

Homework Statement Which of these particles don't follow Pauli exclusion principle and thus have a symmetric wave function? a) Bosons b) Fermions c) Quarks d) All particles follow Pauli exclusion principle Homework Equations None. The Attempt at a Solution I think that...

Homework Statement Water Flows upward throw the pipe shown in the diagram at 96 L/Min. If the pressure at the lower end is 80kPa, find the velocity of the water is at both ends and the pressure at the upper end. Assume that the density of water remains constant throughout the tube and that...

Homework Statement Water Flows upward throw the pipe shown in the diagram at 96 L/Min. If the pressure at the lower end is 80kPa, find the velocity of the water is at both ends and the pressure at the upper end. Assume that the density of water remains constant throughout the tube and that...

So that's the question and I'm stuck on Part b. I don't even know how to approach it. I know A1= 3A2 but I don't know A1 and I need V2 and I don't know V1 or A2. I'm just confused as to how to do this. Please help!

Can someone explain why pressure is transmitted equally to all parts of an enclosed fluid, as stated in pascals principle ? Why doesn't the 'pressure increases with height' rule play a part ? Is it because the volume of the liquid will always stay the same? But then so what ?

Homework Statement Let B=\left\{{\frac{1}{2},\frac{2}{3},\frac{3}{4},...}\right\} Prove sup B = 1Homework Equations Archimedean principle: Let a<b and a>0 \exists n \in{N} such that an > b.The Attempt at a Solution Its trivial to see that 1 is an upper bound for B and B is nonempty, so B must...

Homework Statement A circular cylinder, of cross sectional radius r = (2 + A) m, f oats in equilibrium on the horizontal flat surface of a liquid. The horizontal plane through the axis of the cylinder is parallel to the fl at liquid surface, which is very large in extent. A cartesian...

Hi, Consider a laser source of frequency f. This source is projected to a target at a distance D, so that the light needs time T = D/C to reach the target. I will consider the particle behavior of light in this situation. I will study the motion of one of the photons. At the exact time T/2...

Doubts about wave particle duality I know that a wave packet is formed by superposition of several individual waves having different wavelength.And the resultant wave has varying amplitudes.And from these amplitudes we can find the likeliness of the object to be in that position. My doubt is...