3d Definition and 1000 Threads

Forces F1 =j + 3k, F2 = j + k and F3 = 2i + j act at the point (0; 1;2), (1;0;3) and (1;1;0) respectively. (a) Find the total force and the total moment about the origin. (b) Find an equivalent system of forces consisting of a single force acting at the (1;0;0) together with a couple.Ok so for...

Homework Statement The three dimensional wave equation: c∂^{2}u/∂t^2 = ∇^2 u boundary conditions : u(x,y,z,t) = F(x,y,z,t) on S initial conditions: u(x,y,z,0) = G(x,y,z) ∂u/∂t(x,y,z,0)=H(x,y,z) Homework Equations how to prove the uniqueness solution of the above equation...

I'm trying to figure out how to do a Lissajous Curve in 3d. It has a 2d shape in the real world, so if it's in the real world, then there must be a 3d shape to it. Here is the crazy version, it has 8 variants of the last pic layered and it's at 45 45 0 This is the one above and it is at...

Homework Statement See attachment Homework Equations Let u be the angle between AC and AO and v the angle between BE and BD. Ta is the tension at point A and Tb is the tension at point B. The Attempt at a Solution Tried starting with the OAB body and got: -mg + Ta sin(u) + Tb...

I saw Jurassic Park 3d today and started tinkering with the glasses after I got home. Here, I noticed that if I close one eye and look in a plane mirror that the 'lens' with the closed eye is always clear and the 'lens' with the open eye is always dark. I understand that Real-d 3d works by...

Hi everyone, I'm trying to understand circumstellar disks. One term that keeps cropping up in this context is "surface density". The disks, though flattened, are still three-dimensional, so I'm confused about what "surface density" actually means. I can think of a couple of possibilities...

Homework Statement The volume shown lies above a square in the (x, y) plane having corners (4, 1), (5, 1), (5, 2), and (4, 2). The remaining two surfaces are planes defined by z1 = 2x + 4y + 7 and z2 = 3x + 6y + 8. The density of this object is 880.y. Determine a) the volume of this object...

Hi experts, I wonder anyone of you have an idea on whether we can include a discrete component (specifically a capacitor) into an "Ansoft Maxwell 3D" eddy current design. Little more description: I do have a specific eddy current design with a coils. I need to add a series capacitor and...

Homework Statement Find the energies of the second, third, fourth, and fifth levels for the three-dimensional cubical box. Which are degenerate? Homework Equations E = h^2/8mL^2 (n^2 sub x + n^2 sub y + n^2 sub z) The Attempt at a Solution The levels would be degenerate if one of...

I'm trying to find the energies for n levels of a 3D cubical box. Is there a general equation for this?

When I was about 25 I noticed that a 2D photo appeared 3D when looked at through a magnifying glass. First I thought it depended on the lens, but then realized it was because I looked at the picture by just one eye - exactly as the camera lens had seen it in reality. I.e. there is much 3D...

So say I have an arbitrary function and I want to know it's limit as x,y approaches 0. I could test what happens when the x-axis approaches 0, y-axis as it approaches 0 but there are some functions where I'm told that I also need to test what happens when y=mx approaches 0, and then y=x^2 and...

Is this anywhere near correct, I have too many marks for this & it seems too easy for what I've put. What have I missed? Have I? Homework Statement An F-centre can be thought of as e- trapped in an infinite 3D well. Calculate λ of emitted e.m. radiation when transitioning from E3 to lowest...

Does anyone know of a good online 3d calculator that will actually work. Thanks.

Homework Statement The vertices of a figure are given by A(-8, 4, -2), B(-6, 3, 5), and C(-10, 5, -9). What type of figure is ABC? Why?Homework Equations pythagorean theorem: |AB|=√(x^2+y^2+z^2)The Attempt at a Solution I first found the vector AB, BC, and CA by subtracting the components of...

I am dealing with a set of data where I have values C(x,t) for a discrete set of x and t values. Say: x={1,5} t={1,3,7} C={{C(1,1),C(1,3),C(1,7)},{C(5,1),C(5,3),C(5,7)}}. How do I combine this to a list that looks like...

Hey guys, I am back again with a drag related question, earlier I posted a thread asking how I could incorporate wind into a drag equation of sorts to create a 3d graph that shows the trajectory of a projectile. The help I received helped me add head winds and tail winds, however I am now...

Hey guys, I'm new to these forums so I am unsure if this is the right place to be posting this, but here it goes. I have been working on a drag spread sheet using OpenOffice Calc to predict where a potato will land when fired from a potato gun. I have gotten pretty far along, using...

Homework Statement Find the limit as X, and Y both approach 0 of (X2Y)/(X2 + Y4) Homework Equations The equation from above. The Attempt at a Solution I have been doing the technique of approaching from different lines such as y = x, or x = y, x = 0, and y = 0. All of them give...

Hello I have some question that i confused to know them 1-what is difference between Vector and Line in 3D and 2D? 2-how can find the vertical vector on a surface or line? 3-how can find the angle between two vector or line only with their size?( i do it with Inner Product equation but...

Homework Statement Plot the following point: B(-2,3,5) The Attempt at a Solution If I were to plot (-2,3,5), when I make my first movement of -2, it does not move anywhere on the y-axis correct and when I am moving on my Y axis, There is no movement in the z axis?

Is it possible for a surface to be obtained as the solution for a system of differential equations in a 3d phase space? Almost all 3d phase plots I have observed are curves,example the Lorenz system. Is there a general formula that says that a system of n differential equations would...

Homework Help! 3D vectors problem solving! Homework Statement the vector v=(1,√2,c) makes an angle of 60° with the positive z-axis. Determine the angles that v makes with the positive x-axis and the positive y-axis. Explain how many answers there are. Homework Equations dot product...

3D printers are receiving a lot of attention in the news these days, because they are seen to be a potential disruptive technology. However, most devices of this type are very limited in the materials they can work with, mainly fabricating models in plastics like PLA or ABS. Advanced high-end...

Homework Statement The threading die is screwed onto the end of the fixed pipe, which is bent through an angle of 20º. Replace the two forces by an equivalent force at O and a couple M. Find M and calculate the magnitude M' of the moment which tends to screw the pipe into the fixed block about...

i would like to know if the 'angle' between let's say the walls of a room (ie. the intersection of 3 planes all perpendicular to each other) can be represented in mathematical terms, but as a kind of 3D angle- that is to say not as a combination of 2D angles but as an altogether new form of...

I am utilitizing rotation vectors (or SORA rotations if you care to call them that) as a means of splitting 3D rotations into three scalar orthogonal variables which are impervious to gimbal lock. (see SO(3)) These variables are exposed to a least-squares optimization algorithm which...

A room measures 4 m in the x direction, 5 m in the y direction , and 3 m in the z direction. A lizard crawls along the walls from one corner of the room to the diametrically opposite corner. If the starting point is the origin of coordinates, what is the displacement vector in terms of unit...

Homework Statement A block of weight 50N is hung by 3 cables from the ceiling. Each rope ZA, ZB, ZC converges at Z so that they form a tetrahedron. (ZA=ZB=ZC=AB=BC=CA). Find the magnitude of the tension of each cable. a=0 tetrahedron symmetryHomework Equations F=mgThe Attempt at a Solution I...

Hello Everyone I'm currently working on a unstructured quadrilateral mesh for a discontinuous galerkin free surface flow model. I use the half-edge data structure in the two dimensional code. Does something like a half-edge or "half-face" three dimensional data structure exist. Otherwise...

Hi everyone, I'm working on a project where I need to produce a 3D plot for matrix using Matlab. The plot must comprise of both alpha and beta in 3D. Alpha, A is a 320 x 333 x 4 matrix, where each individual layer (i.e. A(320,333,i) for i = 1:4) represents one image's angles. The beta matrix...

Hi all, I've written code that takes J2000 equatorial coordinates for 2 objects and calculates (1) the projected separation of between object 1 and object 2 at the distance of object 1, and the Euclidean (3D) distance between objects 1 and 2. The projected separations should be <= the Euclidean...

Hi everybody, first time poster here. I am working on calculating the force of magnets in a 3 dimensional space. I have found a formula for the magnetic flux density at a distance z from the magnet face at this link http://www.magneticsolutions.com.au/magnet-formula.html, under Flux density at...

Alright, so, I am writing an aimbot for a popular game, and I need a bit of help with calculating the correct pitch angle for the player. The weapon is a bow, so the arrows are affected by gravity. I am trying to find the pitch angle that accounts for gravity and distance from the Entity you are...

Homework Statement Hi. See attached, I need to determine the forces in all members. Homework Equations Sum of forces in X, Y & Z all equal 0. Sum of moments in X, Y & Z all equal 0. The Attempt at a Solution I've drawn the reactions at each support, A, B and C in my 2nd attached...

Hello! I am having an issue with getting any graphs on inductance or induced voltage. In the attached circuit: What I have is a 28Vac source w/ 400hz and 2 coils (R=18.6ohm each) that are connected with a common. In the model: I have a core in the center that will be able to move up...

Homework Statement The temperature ##T## in a region of Cartesian ##(x,y,z)-## space is given by $$T(x,y,z) = (4 + 3x^2 + 2y^2 + z^2)^{10},$$ and a fly is intially at the point ##(-5,6,7)##. Find a vector parametric representation for the curve which the fly should move in order to ensure...

Hi, In 2D I know a simple answer: vector (a,b) is orthogonal to vector (-b,a) Is there anyway similar to that to find an orthogonal vector in 3D?

Homework Statement The 3-dimensional harmonic oscillator potential holds N identical non-reacting spin 1/2 particles a)How many particles are needed to fill the low lying states through E=(3+3/2)\bar{h}ω b)What is the total energy of the system c)what is the fermi energyHomework Equations...

Calculus III, find shortest distance, 3 dimension problem? check my answer please?? What is the shortest distance from the point P = (0, 1, 2) to the line given by l(t) = (1+t, 2-2t, 3+3t)? use distance formula d = sqrt ((x-0)^(2) + (y-1)^(2) + (z-2)^(2)) d^(2) = ((x)^(2) + (y-1)^(2) +...

Hello, apologies in advance if my questions seem rather ignorant. I'm trying my best (and struggling) to understand the topic, but my background in math is weak, and i need the math for artistic purposes. I want to iteratively move and rotate a point in 3D space (move, rotate, move, rotate...)...

In the following two problems I am trying to get a deeper intuition of, the plane has 3 variables and is 3 dimensional and the hyperplane has four variables and is 3 dimensional as well. Can someone please show me why, practically, in the context of these problems? Question with hyperplane...

Homework Statement I just saw the equation R'=RΩ (where ' is dot, or the derivative) in my notes (unorganized obviously), and can't remember what it stands for (rotation matrices?). Can somebody please tell me what this equations means thanks. I know R is some position vector and Ω is the...

Homework Statement I just saw the equation R=R'Ω (where ' is dot, or the derivative) in my notes (unorganized obviously), and can't remember what it stands for (rotation matrices?). Can somebody please tell me what this equations means thanks. I know R is some position vector and Ω is the...

Hello, this is my first topic/question, thanks for reading thus far... It is very easy to find explanations about the general path that the solar system takes when it orbits the center of our galaxy, when viewed in 2D from above, a circle around the center some distance away from that center...

Hello, If a rotation of a 2-d disk about a 1-d line can produce centrifugal gravity, is it right to infer that rotation of a 3-d volume about a 2-d plane would create gravity, observable in the 3-d volume? It is confusing to think about the direction of this gravity, if it exists...

Hi everyone, I'm trying to design a simple model by using Comsol Multiphysics. I set an inlet concentration of a species "cp" that will be adsorbed to a circular surface located at the center of the microfluidic cell (I named the concentration of adsorbed protein "cpl" ). I used laminar flow...

Homework Statement Trying to figure out how to model the relationship between two 3D points, A and B. Both points have visibility to 2 common reference points, C and D. Bearing and angle readings are available from both A and B to the reference points C and D. The reference points C and D are...

I'm creating a computer program and I need to see what's most efficient. I need another program [lol] that I can input 3d points in and have it create the function. the points are this v e t 100 500 3...

In a 3D plane, there is a point with it's X,Y and Z coordonates known and a second 3D plane within the first plane with it's origins X,Y and Z coordonates relative to the parent plane origin. How do I find the X,Y and Z coordonates of that point relative to the origin of the second 3D plane...