What is 2d: Definition and 1000 Discussions

Homework Statement You are designing a missile defense system that will shoot down incoming missiles that pass over a perimeter defense post. The set-up is shown below. An incoming missile passes directly above the defense base. Radar at the base can measure the height, h, and speed, v1, of...

Hello, in order to numerically solve a physics problem I think I need to add 2 (infinitesimal) rotations of one and the same segment each around a different point in 2D space in one iteration of numeric approximization. How does this addition work out? Is it the sum of the vectors connecting...

Homework Statement hello everybody, I am trying to obtain the flow velocity in two dimensions u(x,y) for the case of a flow past a circle. The equations to solve are: \vec{\nabla} p = \mu \vec{\nabla}^2 u \vec{\nabla} \cdot \vec{u} = 0 I am very blocked at the moment and I...

Came across this one in my freshman physics book: A particle of mass 1m is traveling along the x-axis at velocity V1. It collides elastically with a second particle of mass 3m traveling at velocity V2. The first particle (1m) moves off at 0.92m/s at 48º to the x-axic. The second particle (3m)...

Hello, I am using Maxwell SV to model the magnetic field inside a solenoid coil. I am currently using the eddy current solver as I have an AC source (167 kHz). When I map the H field in the post processor is the software computing induced magnetic field due to eddy currents in the conductor...

Homework Statement Two balls od the same masses collide, the first one is moving with the velocity v_1, the second is stationary. The angle between them is given by the statement: "the direction of the velocity of the first ball forms an angle \alpha=30^\circ with the plane of osculation of...

Homework Statement OK, I'm posting to clarify if my answer is correct. 1. An airplane is flying with a velocity of 90.0 m/s at an angle of 23.0m\s above the horizontal. When the plane is a distance 115 m directly above an observer that is standing on level ground, a suitcase drops out of the...

Homework Statement The figure shows the circular wave fronts emitted by two wave sources. Make a table with rows labeled P, Q, and R and columns labeled r1, r2, \Deltar, and C/D. Fill in the table for points P, Q, and R, giving the distances as multiples of \lambda and indicating, with a...

Homework Statement The astronaut orbiting the Earth in Figure P4.32 is preparing to dock with a Westar VI satellite. The satellite is in a circular orbit 700 km above the Earth's surface, where the free-fall acceleration is 8.12 m/s2. Take the radius of the Earth as 6400 km. 2. Relevant...

Hey. I want to derive the conductivity of graphene. I'm looking for a formula of the sort: J = \frac{e}{\hbar} n \frac{dE}{dk} D(E) \Delta E where \frac{1}{\hbar} \frac{dE}{dk} is the electron velocity, D(E) = \frac{dN}{dE} is the density of states, \Delta E might be the applied voltage...

A two-dimensional harmonic oscillator is associated with the group Su(2). What is that association? Solutions to the Dirac equation require a pair of spinors at each point? Can we think think of spacetime as having pairs of 2D harmonic oscillators at each point? Thanks for any help.

Homework Statement A Nordic jumper goes off a ski jump at an angle of 10.0 degrees below the horizontal, traveling 108 meters horizontally and 55.0 meters vertically before landing. (a) ignoring friction and aerodynamic effects, calculate the speed needed by the skier on leaving the ramp...

Please Help! Motion in 2D Question Homework Statement A student stands at the edge of a cliff and throws a stone horizontally over the edge with a speed of 15.0 m/s. The cliff is h = 26.0 m above a flat horizontal beach, as shown in Figure P3.24. Homework Equations How long after...

Dear all, I have problem in modelling sloshing 2d flows and validate to another paper. I try to make sloshing 2d flows : a rectangular tank of 2m wide 2m high filled with 50% of water (1m) is force to oscilate from left to right . the water begin to move in an oscilatory way before impacting...

I have asked this question before in another section of the forum but I still don’t have an answer so I thought I would try here. Ok…here goes.. In three dimensions, Poissons equation can be used to model an electrostatic problem in which there is a single point charge at the origin. The...

Hello! Since this is my first post I would like to say I am happy that I joined PF and I will try to contribute as much as I can to this great community. So let's get down to the gist of the problem. You are standing 4m from a vertical wall and 0.8m from the ground. You have a bouncy ball that...

I am interested in solving the null geodesic between two points in the presence of a gravitational mass, assuming that everything takes place in 2 dimensions (i.e., no Z coordinate). The following is known: -x and y coordinates of first point -x and y coordinates of second point -x and y...

Homework Statement Need to prove that a slider crank mechanism fits the Grueblers eqaution, already done for a four bar mechanism no problem, however having some serious problems with the slider crank. If l is the number of links and j is the number of joints Homework Equations Grueblers...

Homework Statement The speed limit in a school zone is 40 km/h (about 25 mi/h). A driver sees a child run onto the road 13 m ahead of his car. He applies the breaks, and the car decelerates at a uniform rate of 8.0 m/s^2. If the driver's reaction time is 0.25 s, will the car stop before...

When one compares the fundamental solution for Laplace's Equation one might note that in 2 dimensions this solution becomes unbounded as r goes to infinity while in 3 dimensions the solution goes to zero as r goes to infinity. Now I understand both mathematical derivations so my question is...

Hi all, I like working with computer graphics so I often work between 2D and 3D computer simulations. For example let’s say you had a square in a XY coordinate system and you wanted to move it to an XYZ coordinate system. Placing it in directly would mean that when viewed along the Z...

relation of fermi energy in 3D is E=h(cut square)k(square)/2m, if i want a relation of fermi energy in 2D,what should i do?

Homework Statement Calculate the speed of the minute hand on the clock (I solved with the assumption of the minute hand being the radius) with the length of 25 cm. How many degrees did the minute hand move through from 12" point to 2" point? What is the average acceleration...

I'm looking, as an observer, at imaging accretion discs and tori around Kerr black holes. The image of the disc/torus is projected onto a 2D grid (a CCD if you like) so all lensing effects etc. are implicit. Basically, I can plot the image after determining the (x,y) coordinates in the 2D grid...

Hi guys, I know it’s not triangle, rectangle, square, or circle, but, can anyone tell me what these three two dimensional plane name in english is (images are attached)? Thank you very much in advance Huygen

Hi, I have created data files by compiling and running a c++ code. Now I need to open and store the contents of these files in Fortran 77 variables. But I am not able to do this. The read command does not return the values stored in the file. The files are having some 2003 lines and 53...

Hi everybody, I am currently working on a small computer programming project, and was wondering if you could give me hand. Say I have two simple, identical balls moving in different speeds and angles towards each other. They hit each other elastically, and weigh exactly the same. The...

Homework Statement A 1.2kg mass moving 2.4m/s [East] has an elastic collision with a 2.4kg mass moving 1.8m/s [North]. What are the final velocities? ------------------------------------- I know that I need Ek before and after the collision, but I'm not sure how to calculate it for this...

Homework Statement I am working on a Matlab code that will solve a temperature grid for a 2D transient heat transfer problem. The code seemed to be working well but when I changed the timestep (to find timestep independance) I noticed that the larger the timestep, over the same duration, the...

Homework Statement What is the center of mass a hollow 2D right triangle having legs of length A and B. The sides of the triangle are also extremely thin. Assume uniform density. Homework Equations \overline{x}=∫xmdx/∫mdx The Attempt at a Solution...

Homework Statement A truck of mass 5kg is pulling a smaller truck of mass 2kg up a slope inclined at 10degrees to the horizontal. The trucks are joined together by a light, rigid coupling. The 5kg truck has a resistance of 8N and the smaller truck has a resistance of 6N. The string pulling the...

I think I'm right when I say that the centroid of a 2D shape is found by the intersection of the lines that separate that shape into two shapes of equal areas. Is that correct? I don't want to (for now) think about it in terms of moments and integrals, because frankly, it's a little confusing...

Hello, I would like to ask something about central potentials. When I am working in 3D, I haven´t got any problem solving the schrodinger equation since I use the following change of variables: -\frac{\hbar^{2}}{2m}\nabla^{2}\Psi+V(r)\Psi=E\Psi \Psi=\frac{\chi}{r} With this change of...

Homework Statement A sniper barrel is exactly one meter above the ground and perfectly horizontal. 1000m away is a target one meter above the ground. if the bullet leaves the gun with a muzzle velocity of 1500m/s will it reach the target? (no, next part is my problem) at what angle should the...

Homework Statement g'day everyone, First of all, i would like to thank everyone on this site. You lot have helped me a lot with my homework over the last couple of weeks. anyway to the question. A golf ball is struck at ground level. The speed of the ball as a function of the time is...

hello i want to model and analyze a 2d river which passes a step, in fluent and gambit, but i don't have any idea how should i define free surface between water and air, here is my geometry: i really appreciate if anybody can help me.

http://www.freeimagehosting.net/uploads/th.67869d8231.gif a disk with radius R and mass M is sticked on axle that goes threw the center of the table. between the disk and the table there is no friction. on the big disk there is a smaller disk without mass with radius r and a weight less rope...

Homework Statement Two billiard balls of equal mass move at right angles and meet at the origin of an xy coordinate system. Initially ball A is moving upward along the y-axis at 2.0, and ball B is moving to the right along the x-axis with speed 3.7$m/s$. After the collision (assumed...

hi, I'm not sure if there is a homework forum for programming but I thought I'd post my problem here; I'm supposed to bubble sort a 2d integer array with elements 15 and 2; this is what my code looks like so far: #include <stdio.h> #include <stdlib.h> #include <time.h> #define cards 15 #define...

Homework Statement Car two is traveling due North and collides with Car one, which is traveling due west. Car One has a mass of 765kg and after the collision it travels at 70km/h, 57 degrees North of West. Car two has a mass of 1100kg and after the collision it travels at 41km/h, 44 degrees...

Homework Statement Car 1 (1500kg) is heading north 80km/h, Car 2 (3500kg) is heading east 50km/h. They collide inelastically. a.) Speed and direction of the wreck (car 1 + car 2)? b.) The kinetic energy lost? HERE I HAVE A PROBLEM: c.) What is the kinetic energy of the two-particle...

Homework Statement A 10.0 g marble slides to the left with a velocity of magnitude 0.500 m/s on the frictionless, horizontal surface of an icy, New York sidewalk and has a head-on elastic collision with a larger 30.0 g marble sliding to the right with a velocity of magnitude 0.150 m/s Find...

Homework Statement A plane attains an airspeed of 620 km/hr. The plane sets out for a destination 1085 km to the north (a 0° course) but discovers that the plane must be headed 20° east of north to fly there directly. The plane arrives in 2.00 h. What is the wind speed? What is the direction...

Homework Statement which of the following pairs of quantities transform under rotations of the axes as the components of a two-dimensional vector? a) (x2, -x1) b) (x2,x1) c) ((x1)^2,(x2)^2) Homework Equations The Attempt at a Solution Dont know where to start. i'd appreciate...

I need to initialize the arrays of an object to zero, but when I compile it, it gives me gibberish. Here's my code:

I have a rectangle i am rotating in 3d on multiple axis. i am trying to calculate the 2d height of the rectangle and I am quite lost. For example, if i rotate the rectangle on the x-axis so the top of the rectangle comes forward and the bottom moves back. i can calculate the height of this...

Homework Statement Consider a monatomic ideal gas that lives in a two-dimensional universe (“flatland”), occupying an area A instead of a volume V. (a) By following the logic of the derivation for the three-dimensional case, show that the multiplicity of this gas can be written...

Hi all, I am learning software development and I need to do something that requires some pretty good mathematics I think. I am not very good and been working to solve this problem for a few days now, any help is appreciated. Here is what I am doing: I need to find a way to convert...

Homework Statement Two traffic signals are temporarily suspended from a cable as shown. Knowing that the signal at B weighs 300N. Determine the weight at signal C. Homework Equations Red arrows show lengths of cables and their components. Answer is : W_c = 97.7N The Attempt at a Solution I...

hello, Part of a little project of mine consists of writing C code to build a image file in .ppm format which can be viewed by the simple program xnview. The image size is going to be 256 x 128. My code below generates a image with a smooth transtiton/graident between very dark red to light...