Local Definition and 491 Threads

When is the next "13.00 Local Sidereal Time" for a UK observer? Anyone with software or equations to work that out?

I wonder if there are coordinate systems that gobally curve and twist and turn and curl, that do NOT admit local orthonormal basis. I know that the Gram-Schmidt procedure converts ANY set of linear independent vectors into an orthnormal set that can be used as local basis vectors. And I assume...

http://www.geocities.com/asdfasdf23135/advcal29.JPG I am wondering whether the above statement is true. "A necessary condition for the constrained optimization problem to have a GLOBAL min or max is that..." Should the word local replace global? I am confused about the method of...

for the equation... y = x^3 - 2x^2 -5x +2 is its local minima at (2.120,-8.061) Thanks

I am not a physics major but have always been perplexed by the apparent paradox of two issues: 1. If we use the Hubble telescope to view items 10B+ years in the past yet the universe is expanding, what was the actual physical location of these bodies at the time the light was produced...

Local Gauge Symmetry ?? Trying to understand local gauge symmetry ================================ I have an undergraduate degree in physics, so I know basic quantum mechanics, but that's all. Still, I'm trying to understannd the concept of local gauge symmetry. I would appreciate if...

[SOLVED] Local Max & Min problem I'm having a real tough time finishing this problem. I have to find the local maxima and minima points for g(x). g(x) = 1 + 4x - 10x^2 + x^4 (dy/dx) = 4 - 20x + 4x^3 I've been trying to factor it to get the max and min points, but I find it...

1. Find the local max and min of x/(1+x^2) The Attempt at a Solution Take the derivative of x/(1+x^2) and set it equal to zero. f'(x)= (1-x^2)/(1+x^2)^2 = 0 This is where I am stuck. My first guess was to factor the top, resulting in (1-x)(1+x)/(1+x^2)^2 = 0, and then cancel the 1+x...

I'm a writer working on my first novel. The genre is science fiction and I'm trying to keep the science part of it as close to the realm of possibility as I can. The setting is in a smaller system about 10 to 50 light years of our system. Can someone name a star and its location that is of...

1) f(x,y,z)=x3-3x-y3+9y+z2 Find and classify all critical points. I am confused about the following: The Hessian matrix is diagonal with diagonal entries 6x, -6y, 2. Now, the diagonal entries of a diagonal matrix are the eigenvalues of the matrix. (this has to be true, it is already...

I have a function that looks like this: http://rpi.edu/~doriad/view1.jpg The function is non analytic, so I have to use something like the steepest descent method with numerical gradients to find the minimum. However, if my starting point is on the left of the tall peak, the min I find is on...

In chapter 4 of Bailin & Love, Supersymmetric gauge field theory and string theory, the authors state that supersymmetry is considered a global symmetry, and we can separately consider it to be a local symmetry. Further, since the supersymmetry algebra contains P^\mu, the generator of...

Say we have a BELL state |B00> = cos(a) |00>+ sin(a) |11> then for a (just one) pair of entangled particles, we keep one on location q, the other one in location w; the one in q forms a system Q, the one in w forms W. ( 'x' in a function like |v> x |w> indicates a tensor product)...

I thought local extremum did not exist at the endpoints of a closed bounded interval, however my textbook claims this. Wikipedia: "A continuous (real-valued) function on a compact set always takes maximum and minimum values on that set. An important example is a function whose domain is a...

Homework Statement Find the stationary points and local extreme values of f(x,y) = xy^2e^-(\frac{x^2 + y^2)}{2} Homework Equations You need to find the gradient for the function and then set it equal to 0. So then df/dy equals df/dx and you can solve for a solution set.The Attempt at a...

I have read a number of threads on acceleration and special relativity, but can't find what I'm looking for. I would like to know, in the context of special relativity, how to compute the acceleration "felt" by an observer, and how to transform this acceleration into different inertial frames...

Homework Statement The velocity of the water in the pipe is given by v1=.5t m/s and v2=1tm/s, where t is in seconds. Determine the local acceleration at points 1 and 2. Is the average convective acceleration between these two points negative, zero, or positive? Homework Equations A...

What kinds of local stores sell pulleys? I can't buy online because of time limit. Are the like physics stores around cities? Or do like Arts & Crafts stores sell them? 91739

[Related concepts: Inverse mapping theorem, transformations and coordinate systems] 1) For each of the following transformations (u,v) = f(x,y), (i) compute det Df, (ii) find formulas for the local inverses of f when they exist. a) u=x^2, v=y/x b) u=(e^x) cos y, v=(e^x) sin y I got...

Homework Statement Classify the local extrema of f(x) = x/2 + cos(x), 0 <= x <= 2pi. Give the exact values of the critical numbers and extrema. Find the absolute (or global) maximum and minimum values of the function. The Attempt at a Solution So i need to find the critical numbers...

What is the estimated value of the local star formation rate (SFR) and how accurately do we know this number?

Since there is a significantly-above atomic limit to the allowed sharpness of an (approximately zero-dimensional) needle point due to its local electric field, would there be a similar limit to the keenness of an (approximately one-dimensional) razor edge?

Homework Statement Sketch a graph of a function f that is continuous on [1,5] and has no local maximum and minimum, but 2 and 4 are critical numbers. Homework Equations The Attempt at a Solution Knowing 2 and 4 are critical numbers, I formed the base function x^{}2-6x+8. Not sure...

in zener tunneling phenomena, are the carriers locally generated or non-locally generated? i.e, should we assume the process as though it were generation of holes in the valence band and electrons in the conduction band? i hope someone could shed some physics on this concept. thanks.

1. According to the First Derivative Test for local extrema, if f' doesn't change sign at c, then f has no local extreme value at c. But for a question on my book, f(x)=(4-x^2)^(-1/2), the critical point is 0, but i think it doesn't have local extreme because the derivative doesn't change sign...

http://arxiv.org/abs/0710.3740 Masses for the Local Group and the Milky Way Yang-Shyang Li (1), Simon D. M. White (2) ((1) Kapteyn Astronomical Institute, (2) Max-Plank-Institut für Astrophysik) 10 pages, 5 figures, Submitted to MNRAS (Submitted on 19 Oct 2007) "We use the very large Millennium...

One approach to get a relativistic QM might be to take hamiltonian as sqrt(p2c2 +m2c4). But apparently this does not work because expanding H in inverse powers of c2 will lead to higher order derivative in space. Apparently, one reason this is bad is because higher derivatives mean that the...

I came across this quote recently: "The general theory of relativity teaches that the inertial mass of a given body is greater as there are more ponderable masses in proximity to it; thus it seems very natural to reduce the total inertia of a body to interactions between it and the other...

As far as I can understand space is af manifold with some metric on it. A manifold is described with some charts (coordinates), but how do I relate these coordinates with ex. physical coordinates of some particle. Is it like this: if I'm in some laboratory I make some cartesian coordinate...

Is BM “Bohmian Local” actually Local Is BM “Bohmian Local” actually Local The debate over “local” as defined by Bohmian Mechanics compared to the “local” described by “Einstein Local” and “Bell Local” constantly invades and disrupts the discussions of various threads. This thread is to...

Hi pervect I was going to put this material in the thread where we discussed this topic but I'm unable to locate that thread. Sorry for the unorthodox creation of a new thread for this. I just thought it was important to talk about. :) I've been thinking hard about our discussion about the...

I find the one on wikipedia to be a bit intimidating. It says that... "A topological space is said to be locally path-connected if it has a base of path-connected sets." We have really not covered this notion of "base" in my course, and even though I know what it is, I don't have any...

I have to prove the map g:torus --> (S^2 3 dimensional sphere of radius 1) is a C infinity map in my assignment. The torus is parameterized as x(u,v)=(3+cos u)(cos v) y(u,v)=(3+cos u)(sin v) z(u,v)=sin u The map g is given by g=[6yz/(x^2+y^2+z^2+8), 3-sqrt(x^2+y^2), -xz/sqrt(x^2+y^2)] I...

There is a local physics projects for juniors taking physics. I need some good ideas, can anybody suggest some?

Preamble: I have yet to find a reason to abandon my support of a LOCAL interpretation of QM; especially in relation to EPRB. It is therefore my hope that we might here bring the issue to a head. Given the frequent verbal misunderstandings across the LOCAL--NONLOCAL divide, it is also my hope...

Local maximum point... Homework Statement f(x)=xe TO THE POWER OF -ax x E R a > o Show that f(x) has a local maximum and express this point's coordinates in terms of a.The Attempt at a Solution I think dy/dx = -axe TO THE POWER OF -ax Correct? I don't know where...

I'm interested in studying LOCAL theories within QM. I have the impression that the following theories claim to be such: MWI (Everett) RQM (Rovelli's Relational QM?) QFT (Originated by ?) LQM (There's a book titled ''Local QM'' as I recall.) + Questions: 1. Are there any other LOCAL...

Marco Genovese has put out a review that fairly well summarizes where things are at in tests of Bell's Theorem. He has done similar papers previously, and the references are quite comprehensive (there are 505, and they cover the spectrum). Research on Hidden Variable Theories: a review of...

So I've been working on this problem. I am given the metric in Kruskal coordinates, so ds^2=32M^2exp(-r/2M)/r(-dT^2+dX^2)+r^2(dθ^2+sin^2(θ)dΦ^2) And the path of a particle is X=0 T=λ θ=π/2 Φ=0 And the path of the observer is X=-1/2*T+1/2 θ=π/2 Φ=0 And I am asked to find the 3...

Has anyone heard the word "Tret/treat"? (Not sure how it's supposed to be spelled.) It's used interchangably with treated, and pronounced to rhyme with 'bet'. Its a word I've always been familiar with, but was recently told that once you get more than a few miles outside of Hull no one knows...

How do you name a physical quantity that can be defined at a given point in space: pointlike? local? Say energy density.

We had an initiative that will prevent government seizures of property, via eminent domain, for purposes private development. I really liked seeing that one. A big fat aye for that one! I have a new approach to law and order taxes. I have always supported taxes for law enforcement, but I...

Carl Brannen is having a real triumph in Hawaii He and the famous Japanese physicist Koide are giving talks back to back today and their slides are on line. It seems like on about half his slides (many many anyway) Koide is referring to two equations of Brannen's which Koide has named "the...

Hi, For a first order Diff Equa. x'=f(x,t) and the IC: x(0)=x_0. with t from [0 to infinity) If f(x,t) doesn't satisfy the Lipschitz condition, can I say for sure that there doesn't exist a global unique solution? I think the answer is "no" but I am not sure. Can you all confirm...

I wonder: Would a meeting of dedicated local realists, to discuss QM, fill a phone booth? (We appear to be such a small minority among the great range and depth of PF participants.) However, before gathering in the phone booth, let's each take advantage of the assembled world media and make an...

The volume form on a Riemannian manifold is usually defined either in terms of a local holonomic frame or orthonormal frame. Since it's defined globally, I would like there to be a global definition, like there is with symplectic manifolds (vol = &omega;n). Is there one?

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what is the essentail difference between local density of states and density of state? It is very difficult to figure it out

For f(x,y) = x^2 + y^2 + 3xy I need to find the critical points and prove whether or not they are local minima, maxima or saddle points. I thought the only critical point was (0,0) since Df = (2x + 3y, 2y + 3x) = 0. Doesn't this make (0,0) a local min? The reason I doubt this now is because upon...

Is the speed of light measurement dependent on the tick rate of different clocks? Hello I want to ask the following questions: If Clock A is undergoing only a natural gravitational time dilation, and possesses 0 rate of change in time dilation, and if it is measuring seconds at a different...