3d Definition and 1000 Threads

I want to graph this vector field -^r/r^2 but I don't know how to do. Any help would be appreciated.

I was thinking about how does the 3D glasses(not the one with red and blue lens) work. My first idea is that the lenses are polaroids with orthogonal polarization. So I got a 3D glasses from a cinema and try to prove it. I wear the glasses properly(with the arms on my ears) and then look at...

If I put these 2 lines into wolframalpha.com it comes up with a solution x = 1 + 2t , y = 2 – t , z = t ; x = -2 – s , y = 3 + 3s , z = 1 + 4s t = -8/5 and s = 1/5 using equations for x & y Solution; x = -11/5 y = 18/5 z = 9/5But the z values do not match so how can these...

How do they convert movies that were shot in 2D to 3D? I recently saw that they were rereleasing Titanic in 3D... Doesn't this require multiple camera angles? or is it more like doing a 'cutout' of the actors and placing them on a Z-Plane? The other method I can think of is recreating the sets...

Homework Statement What is the function f(r) s.t int {d3r.f(r).e-iw.r= 1/w2} where w = (kx,ky,kz) Homework Equations None The Attempt at a Solution I tried to directly take Fourier transform of 1/w2 as \int{ d3r.1/w2.eiw.r}. I started integrating dkx bu calculus of residues, calling the...

I am trying to turn a 3D parametric equation into a vector field for an experiment, but I am not having much luck. [x,y,z]=[r*cos(u),r*sin(u),a*u] is the equation, I'm using grapher on the Mac. I want it all going in a helix, which is what the equation is for. Thanks!

Hi all, I have 3 lists of data where lists; A={numbers}, B={numbers} and C={{y,m,d,h,m,s},{...}} (i.e. C is in the form DateList). I have no problem plotting using DateListPlot for the 2D case (C VS A) but can't seem to plot all 3 sets of data together. Mathematica seems not to be able...

Ok, so I have a problem as follows: A beam is simply supported at joints A, B, C D and E. there is a UDL acting on the BC member The member is 6m long with a UDL of 60kn/m However the tricky part is that this member is 1.2 times higher than the height of the members AB, CD, and DE. So BC =...

Hi I do 3D modeling and lately i have been trying to make some more theoretic diagrams about the whole thing. Sometimes i try to go through ways where math and geometry are needed (or so i think) and my background is not up to it. I'll use this thread to post some initial questions per post...

Hi! It's been like two days since I have tried to make this work, still I got nothing. Searched Google etc. but no help there. I have a three dimensional matrix in form of {{a,b,c}, {d,e,f}, {g,h,i}, ... etc. } with a total of 51 elements, i.e. 51x3 matrix. What I want is to plot it as...

Hi. I've been studying for a test and have been scouring my text for methods of proving points in 3-dimensional space are collinear. The best I can see is that the cross-product of the vectors must equal zero. Can someone explain how to do this a little more clearly?

How much more than is to learn when you go from 2D to 3D? I'm curious to know whether all these problems I solve in 2D are less helpful for when we move to 3D, where there are more elements?

What is the relationship between these? On the TV and LW side, these seem relevant http://golem.ph.utexas.edu/category/2011/03/liang_kong_on_levinwen_models.html http://arxiv.org/abs/1004.1533 http://arxiv.org/abs/1004.1737v2 On the TV and 3D gravity side, this seems relevant...

I'd always assumed it was, since LQG spin foam models are based on BF theory. And it is typically said that in 3D it is BF, and in 4D constrained BF. The 4D quantum case is not known to be gravity, but I had thought the 3D case was. Yet in http://math.ucr.edu/home/baez/week254.html Baez...

Dear all, I having a trouble in defining 2D and 3D stress . As I know Maximum principal stress in 2D and 3D cases is totally different. In which condition we should apply 2D stress formula and when we need to use 3D stress formula?

When you are modelling elements like tubes, the local x-axis is defined along the tubes length. If a unit vector for the z-axis is not applied, modelling softwares defaults to a coordinate system where the local zx-plane is parallel with the global zx-plane. I'm not sure what that means...

I have seen a lot of 3D software users of Modo, 3ds Max, Maya, etc that can produce a very nice looking product designs. These ranges of items made by them include car, building, machine, airplane, household electrical product, etc. They all look as good as the outcome produced by the CAD...

Homework Statement A force of 5N acts along the vector (-4,-3,-1) A force of 2N acts along the vector (-3,-6,5) A force of 4N acts along the vector (-9,-1,8) find the resultant force vector. Homework Equations The Attempt at a Solution i tried to multiply the vectors by the...

Homework Statement Let f be a vector function, f = (xz, 0, 0), and C a contour formed by the boundary of the surface S S : x^2 + y^2 + z^2 = R^2 , x ≥ 0, y ≥ 0, z ≥ 0 , and oriented counterclockwise (as seen from the origin). Evaluate the integral (Closed integral sign) f · dr , directly as...

Homework Statement I have a quantum harmonic oscillator with quantum numbers nx,ny,nz ≥ 0 and frequency ω0. There are three parts to the problem. To me it seems they are out of order, but I'm kind of shaky deriving these. a) Write down the energy level Enx,ny,nz of a QHO in 3d with quantum...

if the first 3D object has 4 points. why use x,y,z to describe 3D? am i confused about one or more concepts? does a tetrahedron skip 3D? a plane plus another point some where off that plane would immediately provide 4 directions to move. one for each point. could these directions not be used to...

Homework Statement An electron is trapped in a cubic 3D infinite well. In the states (nx,ny,nz) = (a)(2,1,1), (b)(1,2,1) (c)(1,1,2), what is the probability of finding the electron in the region (0 ≤ x ≤ L, 1/3L ≤ y ≤ 2/3L, 0 ≤ z ≤ L)? Homework Equations My normalized wave function in the...

Homework Statement [\hat{H},\vec{r}]= ? The Attempt at a Solution The answer is given, and I KNOW that factor of 6 shouldn't be there. The answer should be -\frac{\hbar^2}{m} \nabla Anyway I've always been lurking these forums and I enjoy the discussions here, but this factor is...

I am working on a 3D crane system, the system has three dc motors for y, x and z axis, and i control them with a PWM signal. i need to find the relationship between pwm and torque or torque and duty. could someone help me, thanks

Hi, for all of you we´ve made new user-friendly interactive 3D model of solar system and night sky with real-time planet´s positions. http://www.solarsystemscope.com/ (requires flash) Application in a simple way helps students and laymen to understand the movements of the planets and...

Hi all This is my first time here, so I will do my best to explain what I need help with. I have 2 sets of 11 xyz coordinates of some beads that I would like to plot in 3D. I want to show them in 3 space as a before and after (to represent a displacement of each point). I was able to...

Homework Statement Find the volume of the solid bounded by the curves y = x^{1/3} and y = x when rotated around y=1. Homework Equations Volume with washers: V = \pi \int R(x)^{2}-r(x)^{2} dx where R(x) and r(x) are functions of x defining the inner and outer radii of the washers...

I believe this is the correct place to post this as I believe I'm going to need to solve this as a linear system, however I suppose it might be solvable using trig as well. However, I've been at it for a while and I'm out of ideas and I think I'm missing something silly. Consider the...

Hi. I have a set of samples with small white gaussian noise that form a small part of an ellissoid in 3D space. I'm looking for a way to find the center and the axes directions of the ellipsoid that best fits these samples. This is an overdetermined problem with much more 3d points than...

i don't really understand the dirac delta function in 3D. is it right that integral of f(r)d3(r-a)dt = f(a) where a = constant ,r is like variable x in 1D dirac delta function? so why when i have f(r')d3(r-r') , it picks out f(r)? where r is now a constant and r' is a...

Homework Statement The degeneracy of the nth level above the ground state for a three dimensional harmonic oscillator is (n+1)(n+2)/2 where n takes values n=0,1,2,... A gas of N non-interacting identical lithium atoms (mass 6amu) each having spin1/2 is confined in a 3d harmonic potential...

Was just wondering if anyone here has tried 3D programming. If you have, what language did you write in, what difficulties did you have, and what did you find interesting about it? As of now I know of Direct3D and OpenGL, but, if I'm not mistaken, you can use different languages to write...

Homework Statement So have this theorem defined for transforms on the Fourier kind, and hilbert spaces, on R2 The theorem sets bounds for norms of the functions and the transforms in the hilbert scale I have the proofs for the 2D case given in my lecture notes Problem: Generalize the...

Hello, I read an article about a year or two ago and I cannot remember in what magazine I read it, so I was hoping to generate some leads by reaching out. I want to find it because my professor wants to see it as well. The article was about a team or group of physicists, at a certain...

Homework Statement how to find FA, FB, FC, FD in 3D equiblirium static? Homework Equations W1 = 500kg http://www.flickr.com/photos/djaguank/5450648168 distance (see at image) if you can't see the image, please follow this link http://www.flickr.com/photos/djaguank/5450648168...

Hello, I'm having trouble getting started on this problem. Here's the question: [PLAIN]http://img810.imageshack.us/img810/2464/ee323assn3q3.jpg My issue is in setting up the governing partial differential equation in 3 dimensions. What I've tried so far is setting du/dt equal to the...

1. Three guy wires hold a pole BO as shown. The resultant R of the forces due to the three wires has a magnitude of 1000-N and is directed on the pole BO. Force F2 and F3 have a magnitude of 400-N and 500-N, respectively. The distance from point A to point D is 5-m. Find the tension in cable...

Hello! First post here at the forum. I am a member of the underwater robotics team at my school, and I have been put in charge of building the arm. I won't get too specific about the design of it, but it will include gears, motors, and stuff in between. Luckily enough, my school owns a 3D...

Homework Statement For a system consiting of a single particle of mass m in a box of volume L^3 (Lx = Ly = Lz = L) develop a relation between the number of accessible states, Ω(E) and E Homework Equations E = ((π^2ћ^2)/(2mL^2))(nx^2 +ny2 +nz2) The Attempt at a Solution nx^2 +...

For example. L1: x = 11+3t y = 7+t z = 9+2t L2: x=-6+4t y=-2+3t z=-7+5t I was given this problem, and technically these lines don't intersect, right?

Hi, just got set a 3d Fourier transform to solve but I've never seen one before and can't find any examples online. once the integral is set up I should be fine but I'm not sure how to set it up; What is Fourier transfrom (f(k)) of following 3d function for k=(kx, ky, kz)=(1,2,3) for...

Dear frnds, suppose one have a 3D matrix, A=ones(3,3,3); he wants to have eigen value of A, then, A-Lamda*I=0 where A is 3D matrix, I is 3D matrix. now Problem is our mathematical soft can only do 2D inversion or eigen calculation. Please refer me any info to find out the...

This not so much of a homework proble, but something I need to visualize and understand to do a homework problem. If theeres and atom at x,y,z = 0, and one located at x,y,z, = 1/2 and we pull second atom from its posistion with a force F in anyone of the x,y,z directions, what are the...

I need to take the 3-Dimensional Fourier transform of a point charge potential. I have an integral of this form, but I am unsure as to how to approach this integral. \int e^{-i\vec{x}\vec{k}} \frac{q}{|\vec{x}-\vec{x'}|}d^3x A push in the right direction would be appreciated.

Hi, Can anybody help me to find the polar angle and the azimuthal angle of a given 3D vector? Say we know the ordinates of the two point A(x1,y1,z1) and B(x2,y2,z2). So the question is find angles (Theta and Phi) of the vector AB. Any suggestion would be really appreciated. Thanks. Susantha

Just like we can draw 3D-looking images on paper, has anyone tried to "draw" out a 4D image onto 3D space? It's not really drawing, more like building. Since nobody can visualize 4D, it would have to be done mathematically. I've seen projections of hypercubes onto 3D, but it was still 2D since...

An explanation given to the question, "Why do I look different in pictures versus a mirror?", cited that in a picture one views a 2D image but in a mirror one views a 3D image. This difference can effect the depth perceived in ones face. Is this explanation valid? My take is that the...

Homework Statement In a solid state book I am reading the 3 dimensional electron gas is derived. It says, "An unconfined electron in free space is described by the Schrodinger equation where m is the free-electron mass. The solutions of the equation, phi(r)=1/(2pi)^3 Exp(ik.r) are plane...

For example, how would I plot the fixed vector <3, 4, 3>? I'm not sure if I'm using the correct language; I mean the vector with its tail at (0, 0, 0) and head at (3, 4, 3).Also, how would I plot the plane 11x + 19y + 39z = 88?

I was wondering, after reading a few posts on various things related to 'The clockworks of the solar system' such as angular velocity and orbital periods,in a 3-dimensional sense, are planets orbital paths all over, or are they flat on one plane, varying in only 2 dimensions? i imagine it...