3d Definition and 1000 Threads

  1. J

    Variational Principle of 3D symmetric harmonic oscillator

    Homework Statement Use the following trial function: \Psi=e^{-(\alpha)r} to estimate the ground state energy of the central potential: V(r)=(\frac{1}{2})m(\omega^{2})r^{2} The Attempt at a Solution Normalizing the trial wave function (separating the radial and spherical part)...
  2. C

    Circulation of a 3d vector field

    Homework Statement consider the vector field v(x,y,z)=(-h(z)y,h(z)x,g(z)) wherer h:R->R and g:R—>R are differentiable .Let C be a closed curve in the horizontal plane z=z0.show that the circulation of v around C depends only on the area of the reion enclosed by C in the given plane and h(Z0)...
  3. L

    Balancing a 3d weight vs lift system

    Hi I'm trying to balance any 3d system with various fixed weights by selecting the correct lift forces for points of lift an example system would be the following shape ( view from above , think a plane missing the right wing) where X is a point of weight and L is a lift point (also has weight)...
  4. Ryan_m_b

    Medical 3D printer for personalised orthotic devices

    Orthotics are externally applied devices that modify the structure and function of muscular and skeletal systems. They help patients with a variety of conditions from fracture recovery to degenerative diseases like spina bifida. Personalised devices can take months to hand craft and be quite...
  5. C

    Find 3D point along the line at given distance

    Hello, I have asked this question already but have not been able to get conclusive answer. I have a problem and please let me know if my solution is correct. I have a known point, at location A(x1,y1,z1) and the point B(x2,y2,z2) and I would like to find the coordinates of a third...
  6. N

    Rotation Matrix in 3D: Correcting Errors in 3D Coordinate System Rotation

    Homework Statement Hi I have a coordinate system as attached, and I want to rotate it along the y-axis in the clockwise direction as shown. For this purpose I use R = \left( {\begin{array}{*{20}c} {\cos \theta } & 0 & {\sin \theta } \\ 0 & 1 & 0 \\ { - \sin \theta } & 0 & {\cos...
  7. B

    Completeness of a set of basis vectors in 3D Euclidean space.

    Homework Statement The problem is Exercise 2 in the picture http://postimage.org/image/3ou3x1sh7/ Homework Equations The hint says: can you express and three-dimensional vector in terms of just two linearly independent vectors? The Attempt at a Solution I have no idea where...
  8. V

    Points in 3D space (Related to Calculus)

    The equation for the number of possible connections between n points on a 2D plane is (n-1)*(n/2). What is the equation for the number of possible connections between n points on a 3D plane? Is it the intregal of (n-1)*(n/2)?
  9. F

    If it works in 3D, then it works in 4D

    "If it works in 3D, then it works in 4D" I've been watching Leonard Susskind's lectures on special relativity here. At time 0:59:40 he says, "If the vectors are Lorentz invariant, then if the first 3 components of a 4vectors are equal to the first 3 components of another vector (equation), then...
  10. B

    Rigid Box and 3D Schrodinger equation

    Homework Statement An electron is confined within a three-dimentional cubic region the size of an atom where L = 200 pm. a) write a wave equation for the electron b) wirte a general wave function for the possbile states of the electorn. List any quantum numbers and their possible values...
  11. S

    Rotate 1 plane in 3d space to be parallel to another

    I'm not sure if this is the right forum. I'm actually trying to solve this for a computer program given shape A and shape B i'd like to rotate shape A so a given face is parallel to the nearest face of shape B http://postimage.org/image/shb6kyv6d/ attached image but i can't see it...
  12. Adoniram

    Which Program is Best for Plotting 3D Trajectories?

    Howdy folks, I have been given the opportunity to do some extra credit for my mechanics class. As an assignment, my prof would like to see a 3D trajectory plotted via a program (like Python). My basic assignment is to plot the trajectory of a soccer ball after it has been kicked. I don't...
  13. J

    Converting 2D density (circle) to 3D density (sphere)

    Hi All, I'm looking for help in converting 2D density (objects/area) in a circle to 3D density (objects/volume) in a sphere, the circle and sphere having the same radius and distribution of objects being uniform. To make this problem more intuitive, here's a sample application: both crabs and...
  14. J

    Eigenstate for a 3D harmonic oscillator

    Homework Statement A 3D harmonic oscillator has the following potential: V(x,y,z) = \frac{1}{2}m( \varpi_{x}^2x^2 + \varpi_{y}^2y^2 + \varpi_{z}^2z^2) Find the energy eigenstates and energy eigenvalues for this system. The Attempt at a Solution I found the energy eigenvalue to...
  15. M

    Deriving equation from 3D Euler Equations.

    Homework Statement I've got the 3D Euler equations \frac{\delta u}{\delta t} + (u\cdot \nabla)u = -\nabla p \nabla \cdot u = 0 I've been given that the impulse is \gamma = u + \nabla\phi Homework Equations And I need to derive \frac{D\gamma}{Dt} = -(\nabla u)^T \gamma + \nabla...
  16. K

    Graphing 3D: Techniques to Improve | 65 Characters

    I am really struggling graphing in 3d. here are main problem. I graph out using trace curve, for z=k, x=k, and y=k, each one of them, and I was unable to put them together and generate a 3d picture. For instance, z=xe^(-y). This function is a very weird sheet with two sides tilt in...
  17. E

    3d orbital after 3p?Why not 4s?

    Why Group 15 elements(except Nitrogen) have empty d orbitals while bonding? Aufbau Principle states that electrons are added in orbitals only in the increasing order of energy of sub-shells.Also Bohr Bury rule adds to the above principle that increasing order of energy depends on the value of...
  18. B

    Solving 3D Statics Problem with 800N Lamp

    Homework Statement Three cables are used to support a lamp that weighs 800N. Determine the force in each supporting cable when everything is at equilibrium. Homework Equations ƩF in the x-axis = 0 ƩF in the y-axis = 0 ƩF in the z-axis = 0 The Attempt at a Solution I really...
  19. O

    Problem with 3d plotting in OriginPro 8 Program.

    Goodmorning! :) I am using OriginPro 8 and I am having some trouble doing a 3d plot. I have experimental data of Intensity units vs width vs height. I am trying to make a 3d plot, where x and y are width and height and z is intensity. I did convert the worksheet to matrix and then made the 3d...
  20. D

    MHB 3d cube with x,y,z directional vectors

    How can I plot a 3d cube with x,y,z directional vectors going through it? Mathematica or Matlab or Tikz package Latex
  21. N

    Calculate Magnitude of Moment in 3D

    Homework Statement The turnbuckle is tightened until the tension in cable AB is 1.5 kN. Calculate the magnitude of the moment about point O of the force acting on point A. Homework Equations ƩMO = sqrt(Mx2 + My2 + M2) The Attempt at a Solution First I identified the...
  22. N

    Finding Angle θ between 300-lb Force and Line OC

    Homework Statement Determine the angle θ between the 300-lb force and the line OC. I have attached an image of the question Homework Equations P°Q = PQcos(θ) The Attempt at a Solution I tried finding the vectors AB and OA as well as their magnitudes first O is the...
  23. A

    Find point coordinate on 3D circle knowing three points

    I would like to find a 3D coordinate of a point (X) on a circle, knowing two points on the circle (P1,P2) which represent the circle diameter and another point (P3) NOT on the circle but on its plane. Also known the length of the line from P2 to X, for example d. Another thing that may help, the...
  24. J

    Efficient 3D Vector Reflection: Simplifying Unknowns in Mirror Systems

    Hello All, Let say I have a system of two planar mirrors (M1 and M2), with a known input (I), and a desired output (O2). Here are the parameters: Azimuth of input: A Polar of input: B Azimuth of normal of M1: A+180 Polar of normal of M1: X1 (unknown) Azimuth of reflected ray from M1: A+180...
  25. P

    3D Recipricol Space Mapping of Nanowires by using x-rays

    Hey I have a x-ray setup as in the figure, where alpha is the angles between the incoming x-ray beam and the sample. The x-ray are scattered, and measured by a 2D detector in the two outgoing angles. From this i will get a "slice" of the 3D recipricol map. If a want a 3D map, i think i will get...
  26. D

    Mathematica Mathematica 3D plot color function options

    Hi, I have 3D plot used to represent the amount of light that hits a solar panel. Basically what I would like is a way to have say 10% of the data red, the next 10% of the data yellow etc. The 3D plot is at a peak in the centre and then goes to zero by some function based on data, so there...
  27. Dembadon

    Comp Sci Programming in C++: 3D array string copy

    Homework Statement I am making a Klondike style solitaire game, and I am trying to load a string into a 3D array. I am representing the "Tableau" with a 3D array (we haven't gone over structs yet). I want to represent the spaces which don't have cards with the word "empty". I'm not...
  28. S

    Finding Electric Potential Gradient in 3D FEM Mesh

    Hello, The value of electric potential(∅) is known at every node in a 3d finite element mesh. The relation between electric current density(i) and electric potential(∅) is i=k.∇∅, I am writing a code in c, I want to know how to find the gradient of electric potential(∇∅) at every node so...
  29. S

    How to find gradient of a variable in 3D mapped finite element domain

    Hello, I know the value of a field variable in a 3d mapped finite element mesh. Can anyone suggest an effective method/methods to find its gradient throughout the mesh.
  30. S

    How to Create 3D Diagrams for Enantiomer Reactions?

    hi there, I've got three chemical reactions I'm struggling to put into 3d. 1) CoCl2.6H2O + en.2HCL --> rac-[Co(en)3]Cl3.0.5NaCl.3H2O (using NaOH and H2O2 as catalysts) 2) rac-[Co(en)3]Cl3.0.5NaCl.3H2O + (+)Tartaric acid --> [(+)Co(en)3](+)tart]Cl.5H2O 3) [(+)Co(en)3](+)tart]Cl.5H2O +...
  31. R

    Is Sight an Illusion? Exploring the 2D vs. 3D Debate

    I am sure this question has been asked many times before. I searched for a thread on this topic and could not find one. I am an artist. I am looking for an answer on the nature of sight. What is the best explanation for how sight occurs. Do we see a 3D world illuminated by 2D photons? Can we...
  32. F

    How do we decide if a trajectory is 1D, 2D or 3D?

    Hello Forum, In kinematics we study motion and the trajectories of moving bodies. The trajectory is a line (straight or curved) that joins all the positions occupied by the object in the various instants of time. A trajectory has an equation that contains only spatial coordinates (not...
  33. M

    3D Rotation of a rigid body in Fixed Axes (Not Axes Rotation)

    Dear All, I have come across with a seemingly very simple problem but could not solve it by searching on internet and books. May be I am confused. I want to rotate a 3D body around an arbitrary axis with fixed principal axes. The solutions I found is with Euler angles (Euler rotational...
  34. A

    3D printer supplies and building plans

    Hi everybody. Me and a friend of mine are going to be EE majors this year, so we thought we'd build a 3D printer from the very beginning. Of course we're going to have some instructors helping us out but I need some information about the whole thing before offering anyone anything! First of...
  35. H

    Deformation Analysis: When to Use Plane Strain vs 3D?

    Hi all, I have a question regarding deformation analysis. For materials with non-zero Poisson's ration, when is it justified to use plane strain analysis rather than three-dimensional? Perhaps one case is when we are going to analyze a thin sheet. Are there other cases too? Thanks, Hassan
  36. Y

    Mathematica Mathematica help union/intersection of 3d plots

    I want to do the following: Say I have 4 RegionPlot3D plots, namely A1 A2 B1 and B2. Each of those four plots are region plots so they occupies some kind of region inside the same 3d space. First I want to find and display union of A1 and A2, call it A. Then find and display union of B1...
  37. Q

    3D Rigid body dynamics - Rod over rotating disk

    Homework Statement A thin uniform rod is attached to an axis through its midpoint. The axis is standing on a disk rotating with constant angular speed \Omega about its symmetry axis. The rod's midpoint is located directly above the rotational axis of the disk. Let \theta denote the rod's...
  38. G

    MATLAB MATLAB: Adding 2d plot to 3d surface

    Consider the 3d graph of a quadratic form: 1/2*trans(x)*A*x-trans(b)*x Plot via matlab: surfc(X,Y,Z); add following lines: hold on x=-10:10; y=0.5*(2-3*x); plot(x,y); This plot a straight line which intersects the 3d surface. However, I wish for it be graphed on the contours: i.e...
  39. D

    Electron configuration 3d orbitals

    Hello. I'm having a problem understanding the 3d orbitals when I'm doing electron configurations. When you fill up electrons for let's say nickel, Ni, you get the configuration: [Ar]3d8 4s2, if I'm not mistaken. But what I have read, at least I think I have, the 3d orbital gets really...
  40. C

    Graphing magnetic field of two magnets in 3d space

    I never figured I would encounter a problem as hard as this. Basically, there are two magnets of varying strength at 2 different x, y, z coordinates. I need to come up with function(s) to graph the field in 3d space. Or, at least find the x,y,z point where the two fields cancel out (if they...
  41. L

    How do you find the slope of a line in 3D coordinate system given two points?

    Given two points in 3D, is there a way to find the slope of that line.
  42. W

    Circle-Sphere 3D Intersection Points

    I would like to find a way to get the intersection points of a circle and a sphere in 3d. The center of each and their radii are known. This needs to be a general solution so that I can move the center of the sphere in steps and find the intersection at each step. I am curious if this can be...
  43. D

    C/C++ C++ Rotation function works in 2D perspective but fails in 3D

    I'm making a 3D rotation of a poligon.The problem is when I rotate some points in 2D, it works, but if I use the same function to rotate the same points in a 3D perspective , while rotating the vertices move to the center of the object and remain there. I also wrote the 3D rendering part.At...
  44. G

    Area Under a Curve, 3D, with known end points and curve radius

    I am trying to find out a method of determining the area below a curve. The end points of the curve are known in cartesian space, and the curvature of the curve is known. A diagram of the curve is here, shown in the images belowthis webpage ß must be in radians Where; MD =...
  45. P

    Gnuplot: Plotting 3D Points with splot Command

    Hello all, I am having an issue with the splot command in gnuplot. The format of the data I am trying to plot is shown below: 3.09411 71.75663 -2.17624 3.09238 67.64099 -1.94456 3.10106 73.70542 -2.85122 3.09494 75.71568 -3.49932 3.09846 75.29150 -1.14593 My...
  46. P

    Moment of inertia of system in 3D

    Hey i am working on something and i need to know how to calculate moment of inertia of a 3D system of objects. I know these variables: Mass of whole system Center of mass of whole system Center of mass of each object Offset of each object Mass of each object Moment of Inertia of each...
  47. M

    PDE Helmholtz eq. in 3D + boundary value)

    Hi!This is a quite sophisticated problem, but it’s interesting and challenging! Consider the following case: Let’s say we have a 3-dimensional disk with a radius r_{2} and a thickness d (so it actually is a cylinder with a quite short height compared to radius). We’re interested in solving...
  48. K

    How Can a 3D Pipe Be Unwrapped into a 2D Topology?

    Hi, I am not very strong in maths, so sorry if these sounds simple. If I have a 3D geometry of a pipe which has its surface defined by triangles (such as that in Computational Fluid Dynamics or Finite Element Analysis) and I have the coordinate points for all the triangles, how can I...
  49. V

    3D Potts/Ising model. How to identify boundaries of clusters?

    I am currently working on the 3D potts model in a temperature gradient to identify the critical temperature and critical exponent. I use the Swendsen-Wang algorithm to simulate the dynamics of the system, and I use the Hoshen-Kopelman algorithm to identify the clusters of spins. The problem...
  50. R

    Anyone know about the performance of home 3D printers?

    I've been interested in 3D printers for a while but am not good enough with computers to do my own home designs. I read an article about new software that, along with being easy to make designs into code, can also turn a 2D picture into a 3D object...
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