Principle Definition and 1000 Threads

I think I did most of this question correctly, but I think I might be overlooking a few steps because I might have thought about it too simply. A dinner plate of mass 510 g is pushed 60 cm along a dining table by a constant force of 3.0 N directed 22° below the horizontal. If the coefficient...

The references below describe two interrelated relativistic issues that come up when you try to describe radiation from point charges: 1. We normally expect that an accelerating charge would radiate, but this would seem to violate the equivalence principle. 2. Classical E&M can't describe point...

ZapperZ submitted a new PF Insights post Misconception of the Heisenberg Uncertainty Principle Continue reading the Original PF Insights Post.

Hi guys, really confusing myself over grasping this principle... I think my main problem is understanding datums and how choosing the direction of a positive axis effects the result. I understand that the work energy principle states: Wnet = ½m(vf2+vi2) I have previously been taught that Wnet...

Homework Statement A dart of mass ##m## is dropped from a height ##l##. Formulate the uncertainty principle and estimate the minimum limitations, set by the uncertainty principle, of the accuracy that can be achieved in the lateral ##x## position after falling, given an original uncertainty...

Hi everyone and thank you in advance. My first problem is: if v1=constan in a section S1, it should not be ∑ F = 0 ? Or maybe Σ M = 0 ? Because all forces that i recognize are gravity and pressure, but i never found the equation mg - PS = 0 or something similar. I was thinking about something...

I was reading the Feynman Lectures awhile back and I remember reading something he said about the Uncertainty Principle and it seemed slightly odd to me. I don't remember the exact quote and combing through some of the lectures online I can't quite find it. I've heard it more than once from...

This is one of those question you won't find the answer in any book. From Wikipedia: it is impossible for two electrons of a poly-electron atom to have the same values of the four quantum numbers (n, ℓ, mℓ and ms). But how can an electron know the state (the quantum numbers) of the other...

Homework Statement Homework EquationsThe Attempt at a Solution On integrating the force due to fluid pressure on the cap , I have arrived at the correct result ##ρgπR^2(H-\frac{2}{3}R)## . This in turn would be the force with which the cap presses the bottom. But I would like to solve this...

Greetings, I have a question about the classic Archimede's principle. A ball inflated with air will not sink into water. My understanding is that it will be pushed from all directions by the surrounding water trying to fill the space occupied by the ball. So there will be a pressure downwards...

I know that the way we calculate in Fermat's principle in optics is to take the path length (as an integral) and demand that it be stationary to first order. Now this approach is mathematically the same as calculating a geodesic, or finding stationary action, namely we use the calculus of...

It was important in the proof of BCP that the contraction constant h be strictly less than 1. That gave us control over the rate of convergence of f^n (x0) to the fixed point since h^n goes to 0 as n goes to infinity...If we consider f is contractive mapping instead of a contraction, then we...

I was reading about the Pauli Exclusion Principle and I had a doubt. This principle tells us that a maximum of two electrons can be present in an energy level and the spin of the electrons has to be in the opposite direction. But S orbital can hold a maximum of two electrons. This is fine but...

Homework Statement Homework EquationsThe Attempt at a Solution

I found these two examples in a books which demonstrate Heiseberg's uncertainty relation...

Homework Statement A flotation device is in the shape of a right cylinder, with a height of 0.323 m and a face area of 4.81 m2 on top and bottom, and its density is 0.460 times that of fresh water. It is initially held fully submerged in fresh water, with its top face at the water surface. Then...

Hello! (Wave) Let $u(x,y), x^2+y^2 \leq 1$ a solution of $u_{xx}(x,y)+u_{yy}(x,y)+(1+x^2) e^{-u(x,y)}=0, x^2+y^2 \leq 1$. Show that $\min_{x^2+y^2 \leq 1} u(x,y)= \min_{x^2+y^2=1} u(x,y)$. Is the following right? $u_{xx}(x,y)+u_{yy}(x,y)=-(1+x^2) e^{-u(x,y)}$ $(1+x^2) e^{-u(x,y)}>0 \ \ \ \ \...

I am having some trouble understanding what to use for the uncertainties in the Heisenberg principle. My chemistry book has two problems on this principle. One asks to find the minimum uncertainty in the position of a marble of mass 1.0g given that its speed is known within +- 1.0 mm/s. The...

Hi guys, I wanted to ask something that I am interested on Which is on the traditional sewing machine mechanical mechanism (On the foot paddle part) Image taken from Google. From the image above, a typical sewing machine For such application, what is the "Name" for it? Im more likely wanted...

A block lies on a horizontal frictionless surface, and the spring constant is 50 N/m. Initially, the spring is at its relaxed length and the block is station ary at position x = 0 .Then an applied force with a constant magnitude of 3 N pulls the block in the positive direction of the x...

1-What is the different between the Einstein equivalence principle and the Strong equivalence principle? 2-Is it possible to formulate the Einstein equivalence principle in this way? "For every point in space time, always exist a chart / reference frame in which the metric in that point is...

Homework Statement Find the minimum uncertainty of the momentum of a small particle with mass m=1g, which is confined within a region of width a=1cm. Homework Equations Delta(p)*Delta(x)>=hbar/2 The Attempt at a Solution Delta(p)*Delta(x)=hbar/2 Delta(p)*10^(-2)=hbar/2 Delta(p)=10^2*hbar/2...

The general Uncertainty Principle is written in Griffiths' Intro to Quantum Mechanics 2nd Ed. Section 3.4, Page 109, Eq. (3.139) without dependence on the wave function itself. While it is written in R. Shankar's Principles of Quantum Mechanics 2nd Ed., Section 9.2, Page 239, Eq. (9.2.12) with a...

The principle states that two electrons cannot have the same quantum numbers. And I've read that this applies to "fermions"- protons, neutrons, 1/2 spin particles. But how exactly does this apply to, say, a proton? Sorry if I sound stupid...I've got all my knowledge about this through the...

Hey! :o Let $\Omega$ a bounded space. Let $u_1$ the solution of the problem $$-\Delta u_1(x)=f(x), x \in \Omega \\ u_1(x)=g_1(x), x \in \partial{\Omega}$$ and $u_2$ is the solution of the problem $$-\Delta u_2(x)=f(x), x \in \Omega \\ u_2(x)=g_2(x), x \in \partial{\Omega}$$ Using the maximum...

Hi all, I have the next dude: To utilize the Huygens principle at the boundary of a volume, do we need to know precisely material properties inside the volume? Thanks!

I feel there are several non-eqivalent interpretations of energy-tme uncertainty principle.It is right?And if so,what are those corrects?In particular one that sees it (the uncertainty energy-time ) as a chance of violate conservation of energy for a time sufficently small.I would be grateful if...

"Imagine a machine which is a box with a door. Place an object in the box, shut the door, and the machine shields all interactions between the object and the universe. When I open the box, what will I see? Will it be the same thing I would see if I had placed nothing in the box before closing...

An observer outside the rocket sees a light beam through a rocket that's accelerating. How will an observer inside the rocket see the light beam? (The problem is showed in the picture below) My friends and I had this problem at school today, and we couldn't decide which is right. Here are our...

Homework Statement The Attempt at a Solution As you can see where I have got up to... However I am stuck... In the solution there is no i. In mine there will be. I am unsure how you make the complex number drop out at this stage. I think I'm missing a mathematical trick here... The...

I don't really know how to explain it right off the bat, so I'm going to use an example first: Say 2 coins are tossed. Let H1 = a head is tossed first and T2 = a tail is tossed second. If you create an event space, you get {H1H2, H1T2, T1T2, T1H2}. Therefore, the Pr(H1) must equal 1/2 and...

Homework Statement My homework question says: the uncertainty in length 1 is +/- 0.1 and in length 2 is +/- 0.1 : calculate the percentage uncertainty in V where V L1-L2 is 30Homework Equations V= (1/(L1-L2))^0.5 where L is the length[/B]The Attempt at a Solution So what I did was add...

Homework Statement We know about the equation: ##Fe+2HCl(g) \longrightarrow FeCl_2+H_2##. In my textbook it's written that liberation of ##H_2## prevents formation of ##FeCl_3##. But why?And how?Homework EquationsThe Attempt at a Solution I think it is related to the Le-Chatelier principle . As...

Can the Heisenberg's Gamma Ray Microscope thought experiment derive the Uncertainty Principle precisely? Most derivations I find, the uncertainty is roughly 2h, whereas the uncertainty principle is "hbar over 2". Is there anywhere where there is more precise calculations to obtain "hbar over 2"...

Homework Statement A neutron in the nucleus of an atom can move in a range which is about five femtometers long. Use Heisenberg's uncertainty principle to calculate what velocities one can expect to measure. Homework Equations \sigma_p \sigma_x \geq \frac{\hbar}{2} p = \hbar k Probably others...

Homework Statement Hi Guys, This is the first exampe from Engel's problem solving book. After a long period of no math I am self studying. I do not know where my knowledge deficits lie, and was recommended this site for help. "E1. Starting with a point S (a, b) of the plane with 0 < b < a...

[FONT=Verdana]I'm currently reading https://www.amazon.com/dp/0199236224/?tag=pfamazon01-20. The book claims that, according to the equivalence principle, acceleration and gravity have the same effects. So if gravity slows down time, shouldn't acceleration also slow down time? The book seems to...

for example, is loop quantum gravity/SF in 4 dimensions dual to a CFT in 3 dimensions? does a serious proposal of QG have to respect the holographic principle?

Homework Statement If the 2-subsets of a 9-set are colored red and blue, there is either a red 3-set or a blue 4-set. Homework Equations None The Attempt at a Solution My book first proved for 10 points, the proof given is: Consider first for 10 points. Consider the nine edges joining one...

Homework Statement A parallel beam of electrons traveling in x- direction falls on a slit of width d. If after passing the slit, an electron acquires momentum py in the y direction then for a majority of electrons passing through the slit A. |py|d ≈ h B. A. |py|d > h C. |py|d < h D. |py|d >> h...

Homework Statement There's a conceptual question I've encountered in my reading, wherein we're supposed to determine the validity of a statement: "According to Pascal’s principle, if you increase the pressure enough so that the force at one end of an oil-filled tube increases by 10 N, the force...

Homework Statement In each case, state whether the assertion is true or false, and justify your answer with a proof or counterexample. (a) Let ##f## be holomorphic on an open connected set ##O\subseteq \mathcal{C}##. Let ##a\in O##. Let ##\{z_k\}## and ##\{\zeta_k\}## be two sequences...

Hi All, Is it correct to apply Huygens Principle to a situation in which a wave propagates in a string with fixed ends? I know Huygens principle is related to regular propagation e superposition properties of waves, and all these can be found in the string context, but I am not sure this...

Hi, Can someone please explain this to me? "The axis of rotation for a non-quantum-mechanical object can point any way it likes. The Earth could rotate around an axis ninety degrees from the current one, so that the North Pole always faces the sun and the South Pole always faces away from it...

Mentor Note: This thread has been separated out of a previous one to keep discussion of this particular topic open, since the previous thread has been closed. Sorry, the opportunity to ask questions is just too hard to resist. I'm still searching for the right understanding of equivalence. Or...

The principle states it is impossible to 'simultaneously' know the position and momentum(velocity)of an object. Position is something that can be noted at a particular instant, as from a photograph whereas velocity is something that can only be measured over a period of time,as from a movie. The...

How to calculate how much flowrate from blower i can push water pool 2,75m*1,8m down by 1,25m in 1 sec? Note : Blower Pressure 0.03 bar - 0.035 bar There is an empty room above the water pool with dimension of 2.75m*1.8m*1.7m This process happen in a closed chamber...

Ran across this problem reading another forum, and wonder if PHP allies here. Given a set $X$ of 16 positive distinct integers, you can find non-empty, disjoint subsets $A, B \subset X$ such that $A$ and $B$ have the same number of elements, and $|\alpha - \beta| < 0.0025$, where $\alpha =...

what are the philosophical conclusion one can arrive at from the Uncertainty Principle?

for a stream line flow of ideal liquid (non-viscous) imcompressible the sum of pressure energy per unit volume kinetic energy per unit volume , potential energy per unit volume remains constant mathematically P+1/2roV2+ROGH=constant consider a fluid flowing in a pipe of various crossections we...