Dimensions Definition and 1000 Threads

I am not a scientist just an observer and enthusiast. We have 3 spatial dimensions and one dimension of time. What I have been wondering is... could time have more than one dimension? I mean we percieve time as a continuous line, but can time move in other ways that we cannot percieve, like...

Dear all, I feel this should be a simple problem but I can't solve it. Could you give me a hand? Imagine if an arc is bounded by a rectangle of dimensions width and height. The arc starts in the bottom left corner of the rectangle, and ends in the bottom right corner. The apex of the...

Hi all, I've got this problem (which is attached as q1.jpg). I've tried to solve it, but I'm stuck... my solution is also attached (my_sol1.jpg). PLS help me :-( Thnx TED

Why is it that things appear smaller the farther they are away and bigger the closer they are away? It is almost as if the magnitude of their dimensions (length, width, and height)changes. But in reality it is still the same object. My cup x distance closer to me than the door may appear 1/6th...

Alrighty, I'm working on a three dimensional physics simulator that does every operation in spherical coordinates and vectors, and I'm stuck on figuring out elastic collisions. are elastic collisions essentially trading momentum between the two colliding bodies? I'm assuming not, but i can't...

Sorry for the trivial question. But I'm not a physics student by training and I think I running into problems due to interchanging metrical systems. S = E \times H E \equiv \frac{N}{C} H \equiv \frac{N}{A \cdot m} Also, is there any standard operator for denoted dimensions...

obviously in one coordinate neighborhood it can't.. I'm thinking of a line which smoothly develops into a surface : -----<< what particular properties would this object have.. Thanks :)

Homework Statement Calculate basic dimensions of power using MLT notation. 2. Given information: E= P*t E= .5*mass*velocity^2 The Attempt at a Solution Rearranging E=Pt to P=E/t a) P = (.5 mass * velocity^2) / seconds * seconds^2 b) P = (.5 kg * metres^2) / seconds^3 c) moving to one line...

When physicists talk about 4+ dimensional space are these real spatial/temporal/something dimensions or just mathematical constructs that are the only known way to accurately describe the observed behavior? Take the flatland example... We live on a 2D Plane and see a 3D Object (say a sphere)...

Homework Statement A charge q1 = 5uC is placed at (x,y,z):(1,2,-1). A charge q2 = -2uC is placed at (x2,y2,z2):(-2,1,3). Determine the electric force (vectorized form) exerted on q1. Homework Equations F12= kQ1Q2 / r2 The Attempt at a Solution At first I tried finding the distance between...

According to M-Theory there are 11 dimensions including time. 10 of these dimensions are spatial, so objects can move and therefore have velocity? Correct? According to Einstein's General Relativity whenever an object is not in motion in the three spatial dimensions, velocity is conserved...

Homework Statement Suppose the river is moving east at 5 km/h and the boat is traveling 45 degrees south of east with respect to earth. Find (a) the speed of the boat with respect to Earth and (b) the speed of the boat with respect to the river if the boat's heading in the water is 60...

When explaining the concept of spacetime curvature many popular science books (but I've also seen it mentioned in some textbooks) recur to the difference between intrinsic and extrinsic curvature, and how in a 2-D world with ants or bugs that are two dimensional, they would not be able to detect...

Why is it not possible to have Weyl spinors in odd dimensions?

If T:Mnxn ----> Mnxn then dim(T(Mnxn))+dim(ker(T))=dim(Mnxn) I chose matrices because I thought they would be hardest and I am looking to understand concepts here. Suppose n=2. The dim(Mnxn)=4. Now I need to be able to find the other two values. I also know dim(T(Mnxn))=RANK, well at least I...

Hi, Reading up on dimensions, like the m-theory's 11 dimension model, I'm unsure what is meant by this. Does it mean 7 more dimensions beyond space and time, or does it mean something akin to 11 universes in the multiverse (ours being 1 of the 11)? When relating this to string theory, does it...

How many dimensions are there. I can describe the first 3 spatial dimensions plus 1 of time, but all the others are a mystery. I also read that an equation predicted that there would be 10 or 11 dimensions, if this is true, what equation is that?

This may be way off base, but is there any support for the notion that virtual particles seem to appear and disappear because they move into and out of dimensions that we can't see? I kind of envision them appearing on arcs similar to solar prominences, where plasma follows the magnetic field...

Homework Statement A steel ball with a velocity of 2.7 m/s collides elastically with an identical stationary steel ball, and ends up going at a 40. degree angle with its original path. What is the direction of the other ball? What is the final velocity of each? Homework Equations...

Hello, my question is: A rectangular piece of sheet metal with area of 1200cm^2 is to be bent into a cylindrical pipe having a volume of 300cm^3. What are the dimensions of the sheet of metal ? Can someone please give me a pointer as to how to go about solving this. I struggle with math...

According to Wikipedia the formula for the field created by an aperture (the Kirchoff-Fresnel Integral) is: \Psi(r)\propto \int\!\!\!\int_\mathrm{aperture} E_{inc}(x',y')~ \frac{e^{ik | \bold r - \bold r'|}}{4 \pi | \bold r - \bold r' |} \,dx'\, dy'...

Is it true to say that most higher dimensional spacetimes have symmetries amongst their n extra dimensions? Thanks.

Hello, I want to understand if the 'extra space dimensions' is a realizable physical concept. They are just an assumption made by some theories (string theory for example) but i can't understand it at all. Ofcourse, my 'baby' argument is: -How can they exist since i can move my hand only in 3...

Is there any properties with the curvature tensors in 3 dimensions? (Maybe between the Ricci tensor and the Ricci scalar, they are proportional to each other? ) I heard about it in a lecture, but I can not remember the details. The 3 dimensional case is not discussed in many reference books...

Homework Statement Let \textbf{F}: \textbf{R}^m \rightarrow \textbf{R}^n and \textbf{G}: \textbf{R}^p \rightarrow \textbf{R}^m Prove that ({\textbf{F} \circ \textbf{G}})'(x) = {\textbf{F}}'(\textbf{G}(\textbf{x})) {\textbf{G}}'(\textbf{x}) Homework Equations Assume the single...

Homework Statement Consider integer sequence n_{1},...,n_{r} and matrices A_{1},...,A_{n-1}. Assume im\left(A_{i}\right) = ker\left(A_{i+1}\right) Using the rank-nullity theorem, show that \sum^{n}_{i=1}\left(-1\right)^{i}d_{i} = 0 Homework Equations The rank-nullity theorem...

Are there any exact solutions for two-dimensional projections of 3-body problems?

Homework Statement An m = 6.20-kg clay ball is thrown directly against a perpendicular brick wall at a velocity of 22.0 m/s and shatters into three pieces, which all fly backward, as shown in the figure. The wall exerts a force on the ball of 2660 N for 0.110 s. One piece of mass m1 = 2.20 kg...

I am designing an eddy current brake system for use in roller coaster design. I have the flux density required to reduce the speed to what i want it to be. what i need to do from that is work out the dimensions needed to obtain his flux density. the configuration is for identical magnets...

Detecting Vanishing Dimensions via Primordial Gravitational Wave Astronomy http://prl.aps.org/abstract/PRL/v106/i10/e101101

Is a three dimensional universe not a requirement for electrons to be configured as we know them? Wouldn't atoms at the least have to exist on a three dimensional brane for the electron clouds to exist as they do?

Hi all! I am having great trouble in the last days trying to make MATLAB plot for me a function of a matrix exponential of a variable t. Here's my attempt: first, I define the z-Pauli matrix s_3 and the identity matrix I by: %define the pauli matrices and the identity I% I = [1 0; 0...

I recently answered several questions in the biology forum regarding integrating over the change of voltage with respect to time. Although it wasn't part of the posters' question, I'm not sure about the physical dimensions of this integral. Electrical potential can be expressed as energy per...

Hello, we have been asked: i) State the dimensions of voltage. The work W done to move an amount of charge Q (coulombs) through a potential difference of V volts is given by W = VQ. ii) state it's SI units. Would I be correct to say i) the dimensions are V=J/C or could I word it V=W/Q ? ii)...

I've heard that there can be said to exist 11 dimensions of space and time, only 4 of which are perceptible to us directly. My question is this, is it possible that these extra dimensions are just collapsed gravitationally, and if so could this account for the apparently weak force of...

Hi, Here's a http://blogs.discovermagazine.com/cosmicvariance/2011/03/04/fractal-black-holes-on-strings/" ). Basically, they showed that if http://en.wikipedia.org/wiki/Black_string" is to be expected. However naked singularities would be such a strange thing that it seems safe to...

Consider the following model. Put a lattice of N electrical nodes on a sphere. The lattice doesn't have to be perfectly regular. Each node is connected to others by copper wires that run through the interior of the sphere. The wires do not interfere with each other. In some initial state...

Homework Statement proof at 0,0 g(x,y) is differentiable Homework Equations notes says i have to write in the form fx(0,0)\Deltax + fy(0,0)\Deltay + E1\Deltax + E2\DeltayThe Attempt at a Solution i compute fx(0,0) = 0 and fy(0,0) = 0 but what's the E talking about? what am i trying to do...

Hello! This is my first post but definitely not my last. I am programming a space simulator and my first problem to solve is to make gravitation work properly. If I have two objects at arbitrary positions in three dimensional space I can calculate the net force between them in a straight...

From what I have gathered, M-theory states that there are 11 dimensions. We live in 4 of these dimensions, and I believe the common understanding is that the 7 other dimensions are incredibly small. At the time of the Big Bang, these 3 dimensions expanded along with the universe while the...

Homework Statement A rectangular poster is to be made out of cardboard. The margins on the top and the bottom will be 2 inches. The margins on the sides will be 1 inch. the are of the poster devoted to the printed material must be 300 square inches. (a) To the nearest .001 inches, find...

Homework Statement Two guys are sitting in a cart. At point C, they jump off to avoid the cliff below. How do the dimensions of the set affect the motion (velocity and acceleration) of the railway cart? Homework Equations t = square root[2*(l)/(g)(sinө)] <-- given equation for...

Hello, first post, probably a beginner question, but I am stumped. I modeled a set of data in MATLAB using the finite difference method. I then solved the system of linear equations and the solutions are in an N x 1 matrix. The problem is, I need to use the pcolorcommand to plot it and need...

From what I have gathered, M-theory states that there are 11 dimensions. We live in 3 of these dimensions(unless time is considered its own dimension), and I believe the common understanding is that these other 8 dimensions are incredibly small. At the time of the Big Bang, these 3 dimensions...

What are all the 26 dimensions in the M theory, named?

Homework Statement Find the work done by a force of 3 Newtons acting in the direction 2i + j + 2k in moving an object 2 meters from (0, 0, 0) to (0, 2, 0). Homework Equations Commonly known vector operations. The Attempt at a Solution I found the displacement vector to be 2j...

Hello fellow physicists! Last meeting with my supervisor I had just recovered from disease so all I have left are some equations for the math behind path integrals that don't make to much sense.. I was wondering if, maybe someone can help and clarify what he was trying to get at. It would be...

Hi All, In Ken Onos lecture he mentions Hausdorff dimensions appertaining to prime numbers: 5,7,11 relate to 0 dimension and primes from 13 to 31 as 1 dimension. Are there more dimensions and if so do they also easily appertain to a set of prime numbers? Thanks Chris

I often read claims that string theory cannot possibly break Lorentz invariance. Whether people have feedback right now, or for future reference, I would like to open a thread on the following paper. A Slant on Warped Extra Dimensions

I am currently reading Dirac Equation from Peskin-Schroeder. In a particular para it says, "Now let us find Dirac Matrices \gamma^\mu for four-dimensional Minkowski Space. It turns out that these matrices must be at least 4X4." What is the proof of the above statement? I think (not sure)...