3d Definition and 1000 Threads

Who here has seen it? I saw it today in 3D imax. After my eyes stopped hurting I rather enjoyed myself. Not a bad way to get back into the series.

[PLAIN]http://img337.imageshack.us/img337/3623/pensp.jpg Homework Statement I need to find the equations of motions via Lagrange's formulation when the generalized coordinates are: \vec{q}=[x,y,z]^T2. The attempt at a solution I need to verify whether what I obtained so far is true or not...

Homework Statement A 1125 N force F is supported by cable AD and by struts AB and AC as shown. If the struts can transmit only axial tensile or compressive forces, determine the forces in the struts and the tension in the cable. a = 6 m b = 1 m c = 4 m d = 6 m f = 2 m...

Hi, I just saw this video on youtube, originally from Carl Sagan's 'Cosmos', about a 4th spatial dimension. http://www.youtube.com/watch?v=Y9KT4M7kiSw&NR=1" So what happens when the photons that are traveling in 3D hit an object in a 2D plane universe. To a 2D object it seems like photon...

http://arxiv.org/abs/1011.5049 The Quantum 3D Superparticle Luca Mezincescu, Paul K. Townsend (Submitted on 23 Nov 2010) The minimal (N=1) superparticle in three spacetime dimensions (3D) is quantized. For non-zero mass it describes a spin-1/4 semion supermultiplet of "relativistic...

I often look up at the sky and wonder how far away this or that star/object is. I know that most discernible stars are in our neighborhood, but I have a hard time figuring out just how close they are. Is there a map/graphic that would map all the objects we can see with a naked eye in our...

Curious as to whether there's a formula for calculating the shape of the magnetic field lines, including electro magnets (solenoids). I want to create a 3D graphical display for the magnetic field lines of magnets.

Show that the kinectic energy of a three-dimensional fermi gas of N free electrons at absolute zero is (Mathematica code used) u = 3/5 N Subscript[\[Epsilon], F] Now I know total energy of N particles is this integral u = \!\( \*SubsuperscriptBox[\(\[Integral]\), \(0\)...

Hello All, I am looking for a way to find a point on a line (eg. line 1). This line has a perpendicular which has an intersection with another line in 3d space (line 2). I have the coordinates of line 1 and 2 and their direction vectors (lines have an infinite length). I also have the...

Hi, I'm pondering the relation for the surface integral of a membrane \sqrt{1+\nabla \psi \cdot \nabla \psi} My two questions are: 1) Does this expression have an identical form if the "membrane" is a scalar field in 3 dimensions (like Temperature) 2) How does one derive this result for 3...

I am trying to create a kind of rudimentary 3d positioning system, sort of like a CNC minus the machining aspect. I am just trying to get my very basic design down and I am stuck at how i should get the position data, my first thought was to use an accelerometer placed at the tip of the actuator...

Homework Statement Two lines are given p: \stackrel{\rightarrow}{r}(t) = (4,7,4) + t(2,2,-8) and q: z = 3, x = 7 -y (second one is given in parametric form). Questions: a) find a function f(x) which has a value in x that equals a distance from a point \stackrel{\rightarrow}{r}(x)...

How to calculate 3D Principal stresses? If I got the values of 6 stress tensors: Then I can calculate the values for the 3 stress invariants I1, I2 and I3: I also know the relationship between the stress invariants and principal stresses: So how can I calculate the values for the...

Hi all, Does anyone know how to get Mathematica make a 3D plot with logarithmic axes? I need a, say, 3D version of LogLogPlot. I have a 3D function Rdb[nf, pf] which I want to plot for {nf, 10^10,10^18} and {pf, 10^10,10^18}. I can get cross sections of what I need when I do...

Homework Statement Show that the shortest distance between two points in three dimensional space is a straight line. Homework Equations Principally, the Euler Lagrange equation. The Attempt at a Solution I understand how to do this for a plane, but when we move into three...

i have an object and a 3d direction vector and position for it . I would like to know how do i determine if a certain point X is in the space below the plan determined by my direction ? Here is an image that i have drawn to make it more clear . In this image I've made the vector 2d...

Few days back I posted a question here that dealt with inversion geometry. A point P inside a sphere can be inverted with respect to the spherical surface to another point P' outside. Center of the sphere O,P and P' are collinear and OPxOP'=r^2 I was wondering if it is possible to get a 3D...

Hi there. Well, I got a surface plotted with Mathematica. I've used the Plot3D command for this. But now I want to plot a point in the same graph. The thing is I've used Taylors polynomial of second degree, and I want to "see" the point around which I'm making the approximation. But I don't know...

Hello everybody, I am studying a theorem and I want to convert a function of one variable into a function of two variables. At first steps I am really confused and don't know what to do. Can you help me with this step: function with one variable: given; f(x), f(0)=f(1)=0 on...

Hi all I'm new to scilab. I was given an assignment to use scilab to draw a 3D surface. It needs to be creative and clearly noted what the codes mean. I'm totally freaking out with my assignment because it is due Tuesday next week. I would apprecriate anyone who could help me. Thanks for...

hi, why do we need to have additional complexity to 3D space? we know that space holds information. but I'm not aware of any information in the universe which is held by "time dimension".. isn't there only changing space and our brain does the "time job" with memorizing and sorting...

Hi, I'm looking for an efficient way of achieving the following, but having trouble thinking it through: Let's say I have a triangle in three dimensions with vertices A, B and C. Let's say I also have a three dimensional coordinate D. I know the x and z component values for D and I am...

Homework Statement A uniform steel plate 18 in. square weighing 87.8 lb is suspended in the horizontal plane by the three vertical wires as shown. Calculate the tension in each wire ((a)TA , (b)TB, and (c)TC). Homework Equations \SigmaM=0 The Attempt at a Solution both A and B are...

1. Hi I am writing a program to calculate 3D vectors for visualization and I am testing textbook problems such as: "If vector c forms an obtuse angle with the 0Y-axis and is orthogonal to both vectors a = 3i + 2j + 2k and b = 18i - 22j - 5k Find the components of c if its norm...

Homework Statement Replace the three couples with a single resultant couple. Specify its magnitude and direction of its axis using angles to the positive x, y, and z axes. Homework Equations M = r x F (r cross F) The Attempt at a Solution I'm pretty sure I want to resolve the...

There are 2 objects. Object 1 is stationary and Object 2 is in motion. Object 1's position in the 3D world is (x=0,y=0,z=0). I have Object 2's velocity (also in x,y,z directions). I need to calculate the speed at which Object 2 is moving towards (or away from) Object 1. Keep in mind that this...

Homework Statement A given surface contains all points G such that the distance from G to the plane z=4 is double the distance from point G to the pt. (2, -3, 1). Find eqn for the surface. Homework Equations I thought the distance formula for a point to a plane would help, but I can tell...

Hello I am not an expert in physics and only have minimal exposure. However, I have been struck by something recently that I wanted t bring up with experts in the field. I was discussing with a colleague the other day, the ability to imagine 3 dimensions. My colleague stated that most...

Homework Statement A system of cables suspends a crate weighing W = 420 lb. The dimensions in the figure are as follows: h = 20.9 ft, l = 5.70 ft, x = 7.05 ft, \theta = 36.0\circ, and \phi = 20.0\circ. Determine TA, TD, and TE, the tensions in cable segments CA, CD, and CE, respectively...

What would a 3D ball look like if it were partially in 4D space when none of the 4th dimension is visible to the 3D observer? The equivalent question in flatland is: What would a 2D filled circle look like in flatland if it was partially in 3D? I think that there the answer would be a...

Homework Statement A system of cables supports a bucket. The dimensions in the figure are as follows: x_1 = 4.80 ft, x_2 = 1.70 ft, y_1 = 1.10 ft, y_2 = 3.30 ft, z_1 = 2.55 ft, and z_2 = 3.10 ft. If the bucket and its contents have a combined weight of W_1 = 17.5 lb, determine F_A, F_B, and...

Homework Statement A flashlight located at the origin, (0, 0, 0), shines a beam of light towards a flat mirror. The beam reflects off of the mirror at (8, 4, 1) and then passes through (10, 8, 5). What is the equation of the plane that contains the mirror? Express answer in linear form...

I have a plot of radius and temperature. I want to plot it in 3D by rotating it about the origin to produce a 3D plot. I can not figure out how to do this in Mathematica without doing it by hand and then plugging it into the Plot3D function. Any advice would be greatly appreciated. The...

Hi everyone, I'm a software engineer (sorry in advance if I made/will make some math mistake) and I'm trying to calculate the projectile motion from one point to hit a specific target in a 3d space so that the parabola will lie on an arbitrary plane. Is several days that I'm trying to...

So, there was a big long post here with examples and such, but then my internet crashed. So screw the examples, I'll just get straight to my question. When seeing if a limit exists in 3d (with the limit being (0,0)), I noticed that we often try the lines x=0 and y=0 first. Are these always...

** I accidentally posted this in the pre-calc math section first, but I think it's more applicable here...sorry** Homework Statement I need to find the intersection point of two vectors. For vector A, I have it's start point (0,0,0) and it's magnitude in components (-.41, .28, -.08)...

Homework Statement I need to find the intersection point of two vectors. For vector A, I have it's start point (0,0,0) and it's magnitude in components (-.41, .28, -.08). For vector B, I only know it's start point (-2.70, -.45, -.21) I also know that the angle between the two...

Homework Statement A system of 20 neutrons are confined in the region 0<x<3L 0<y<L 0<z<2L With L=10^{-15}m If each eigenstate can accept 2 neutrons (corresponding to the 2 possible spin states) what is the total kinetic energy of the system? Homework Equations I found the...

Homework Statement The vertices of triangle are (2,0,0) ; (0,3,0) ; (0,0,6) . Find the area of triangle. Homework Equations The Attempt at a Solution is it right that i put in determinant like Area of triangle = 0.5 | 2 0 0 | | 0 3 0 | | 0 0 6 | = 0.5 (2* 3 * 6)...

How can I calculate the curvature of a 3D hyperboloid? I mean, what parameters do I need to calculate the intrinsic curvature? I guess to calculate the extrinsic curvature as seen from a 4D space I would just need a curvature radius, right? Thanks

Can someone point me to 3D model of surface of the land and ocean floor of the Earth, or a grayscale elevation map so I could make my own 3D model from it. I was curious - I wanted to play a bit with such "flat" (rectangular i.e. not spherical) 3D model of Earth's relief by placing a flat...

Hey, I've done quite a bit of Mechanics work in the past... But I really don't even know where to start here. For some work I'm doing, I need to calculate the resulting velocity vectors when 2 objects collide. These 2 objects can be any shape, any mass and going at any velocity independently...

Homework Statement Ok I have a bunch of questions, please bare with me and i'd appreciate it VERY much if you could help me with these! 1. Assume that you are given the equations of three planes. Without solving the system, describe a "test" with rationale, that you could use to determine...

I'm here again bothering you, I have this problem, but have no idea about how to start the problem solving: Homework Statement The USPS will accept packages only if the length plus girth is no more than 108 inches. Assuming that the front face is square, what is the largest volume package...

I just got back from the cinema an hour ago and brought my 3d glasses home,i know these glasses work by only allowing light that oscillates in certain dirrections through the lenses,and each lense lies perpendicular to the other,allowing only one set of light through each lense,making you to see...

I'd like to make a single 3D graph that contains a scatter plot and a plane. Ideally I'd like to import the data for the point from an excel file, but if I have to punch it in, I can find a few hours to kill. Anyway, can anyone help me with the code for this? I can get a 3D scatter plot where...

Hi, How can I plot some 2d graphs in a 3d fashion like the following picture using excel or matlab? Any idea is appreciated.

i have a vector ai+bj+ck is the resultant equal to sqrt(a^2+b^2+c^2). if so how do i explain it mathematically? i know the resultant of a 2d vector is equal to sqrt(a^2+b^2) and it can be proved from pythagoras theorem? any ideas??

I have 2 variables and data points corresponding to them and so would like to plot this (I think using the plot3 function for a 3D graph) but I'm having trouble writing my code. Each variable ranges from 0 to 1 (in 0.1 intervals) and so this would be the x and z axis, and I have data points...

hi there, i am looking for the site about sharing 3D models, (like 3dcadbrowser) if you know, can you help me?