2d Definition and 1000 Threads

Homework Statement A moderate wind accelerates a pebble over a horizontal xy plane with a constant acceleration = (4.60 m/s2) + (7.00 m/s2). At time t = 0, the velocity is (4.4 m/s). What are magnitude and angle of its velocity when it has been displaced by 11.5 m parallel to the x axis...

Homework Statement A firefighter, 50.0 m away from a burning building, directs a stream of water from a fire hose at an angle of 40.0° above the horizontal, as in figure. If the speed of the stream is 30.0 m/s, at what height will the stream of water strike the building? Homework...

Homework Statement A skateboarder shoots off a ramp with a velocity of 5.1 m/s, directed at an angle of 58° above the horizontal. The end of the ramp is 1.4 m above the ground. Let the x-axis be parallel to the ground, the +y direction be vertically upward, and take as the origin the point...

Homework Statement A person standing on top of a hemispherical rock (a dome rock) of Radius R kicks a ball (initially at rest on top of the rock) to give it horizontal velocity Vx A. What must be it's minimum initial speed if the ball is never to hit the rock after it's been kicked? B...

Homework Statement A particle undergoes simple harmonic motion in both the x and y directions simultaneously. Its x and y coordinates are given by: x=asin(wt) y=bcos(wt) . Show that the quantity x(dy/dt) - y(dx/dt) is constant around ellipse, and what is the physical meaning of this quantity...

MTd2 spotted this interesting paper by Florian Conrady (Perimeter postdoc). To go with this paper the author has provided two animations to watch: http://www.florianconrady.com/simulations.html The second one of these two simulations ("Model with 2D interactions") shows the crystalization of...

Homework Statement A mortar elevated to 60 degrees scores a hit 15 m up a building 30 m away. With what speed was the shell fired? I know I have to find the launch velocity, or VL. Here is a quick sketch i did: Homework Equations s= vot + 1/2at2 v = s/t The Attempt at a...

Homework Statement An arrow is shot with an initial velocity, V0, at an angle, \Theta, with respect to the horizontal. It reaches a maximum height of 2m above the launch point before hitting its target. The target is 15m horizontally, and 1m below the launch point. Find the time in the air...

Homework Statement A stone thrown horizontally from a height of 6.02m hits the ground at a distance of 13.90m. Calculate the initial speed of the stone. Neglect air resistance. Homework Equations 1. v = v0 + at 2. x = x0 + (1/2)(v0+v)t 3. x = x0 + v0t + (1/2)at^2 4. v^2 = v0^2 +...

If the magnitude of acceleration is constant, and acceleration is perpendicular to velocity, is speed constant? Also, is speed not constant when the magnitude of acceleration is not constant? How would I show this? I tried to do this: If position is p(t)=(x(t),y(t)), then velocity is...

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...

I would like to simulate the flow around a 2D airfoil up to M=0.9. Could you please recommend me some bibliography?

I'm writing a little 2D physics engine. The collision response is calculated by working out the impulse (and so, change in momentum) on each object, and takes into account the objects' velocities, angular velocities, and the fact that the collision normal may be in a different direction to the...

Hello, Does anyone know how to write codes for constructing the matrix of Hamiltonion of 2D square Tight-bonding model. Then diagonalize it. Any language is OK. (Fortran is best)

Hi guys, I don't know if this question has been asked before, but I searched the forum but didn't get answer to my question. I was looking at the transition when a core electron is knocked off by energy and that an upper level electron replaces it and x ray is released. Question, why are there...

I was just wondering is there any major difference between the projectile motion of a 2D object vs the projectile motion of a 1D object or just a point. For example in a 2D world if someone just threw a square, would the calculation of the trajectory be a lot more complicated then calculating a...

ok this seems like a predominantly maths problem but i need it for a little project of mine related to classical dynamics. So i have 2d numbers Xk, which are constrained by the relation that their sum is n. what i need to find out is the number of possible permutations of the 2d numbers (Xk)...

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

Homework Statement \omega_{x} = \omega \omega_{y} = \omega + \epsilon where 0 < \epsilon<<\omega Question: Find the path equation. Homework Equations I started with the 2D equations: x(t) = A_{x}cos(\omega_{x}t + \phi_{x}) y(t) = A_{y}cos(\omega_{y}t + \phi_{y}) The Attempt at a Solution...

Hi... I have four vectors that I need together in one plot and also they should start at (2,2) Vector A is a=[5 0] B is b=[0 2] I obtained unit vector and I need something similar to http://www.scribd.com/doc/13353344/Fundamentals-of-Electromagnetics at page nine I know the...

hi, so this is actually for a program I'm writing, but it's definitely more of a math question than a programming question. basically, i have an object that gets detected by a webcam attached to a computer. the object is just a piece of paper with a pattern on it, so it is, for the purpose of...

What's the difference between first and second order phase transitions. Could anyone give me some simple examples of both? Thanks.

If someone could supply the code to plot this graph in Mathematica would be awesome. Would also be best if it checked the y's at units of t {0,1,2,3...,inf} y >= 340 Plot[100 (t) - 340 (t/2), {t, 0, 20}] y< 340 Plot[100 (t) - 115 (t/2) , {t, 0, 20}]

Hi, I think i should have posted here instead of where I posted before. I don't know how I missed the homework help section... anyway Well, I'm required to solve this heat transfer problem. T1 is 25c and q'' is 100w/m2 Ok, so I can get it to do it in 1 dimension and my numbers...

Hello, I just need to know whether or not surfaces with zero size in the third dimension, 6x8x0, is considered two-dimensional. The surface is there all the time. It has a location in the third dimension, so wouldn't it be a 3D object? I am not sure whether I should call a flat surface (as...

Hi all, I am working on the problem below, and I wrote the code, but it's not working. Can anyone help me out? And even any ideas on how to improve the code to make it more succinct? http://i25.tinypic.com/2v0zi8m.jpg Basically, it is a 2D conduction problem with convection heat...

Is a curve (Say 'S') 1d or 2d? I ask this question because for so long i was under the impression that it was 2d, since we need a 2d cartesian plane to draw and describe a curve. But then i read in a popular book that it was 1D, which is hard to believe. so which is it?

Linear momentum 2d collision Homework Statement Two particles A and B of mass m and 3m respectively, A collides with B. Find the coefficient of restitution e if \textbf{v}_{A} is purely in the \textbf{j}-direction. Velocity of each particle before collision. \dot{\textbf{r}}_{A}=9...

Hi there...I need ur help on these questions: 1) Can H2O exist as a vapor at -40oc,As a liquid? Why? 2) What would be the general nature of Constant volume lines on Phase (P-T) diagram? Both questions are from Engg. Thermodynamics-Moran,Shaprio(Things engg. think abt section) Also, does anyone...

Hi everyone, I'm currently working on coding a finite element heat problem in Matlab that is as follows: I have a cross section of a beam made of an isotropic material (concrete) that is placed in a furnace, and the outside temperature is raised at a constant rate. I am interested in...

An SR question again, exam on monday. Homework Statement I'm given a 2D metric as: ds^{2}=x^{2}dx^{2}+2dxdy-dy^{2} I have to first find the contravariant and covariant components of the metric, or g_{ab} and g^{ab} Homework Equations General expression of a metric tensor...

Hello. I was asked to import a number of data to mathematica from an output file for wien2k (based in fortran). The thing is, I have to draw a graph that considers a matrix full of data in three dimensions, but the graph itself should only have two parameters. To sum up: how to represent 3D data...

The result is well known, but i need more details about the integral below \int \mathrm{d}^2x \frac{1}{|\mathbf{x}|} e^{- \mathrm{i} \mathbf{q} \cdot \mathbf{x}} = \frac{2 \pi}{q} I've done the Fourier transform of the Coulomb potential in 3D. But failed to get the right answer in 2D...

Please help As a science fair project, you want to launch an 700 g model rocket straight up and hit a horizontally moving target as it passes 29 m above the launch point. The rocket engine provides a constant thrust of 15.0 N. The target is approaching at a speed of 15 m/s. At what...

Homework Statement Two objects are involved in an elastic collision object 1 has a mass of 20Kg while object 2 has mass of 25Kg the initial velocities of the objects are unknown but neither of the objects are stationary Object 1 is moving 35m/sN30E after collision and object 2 is moving 15...

http://upload.wikimedia.org/math/1/9/8/1983171154842b0b061fc42aa5eb7642.png" How to rewrite this 2D Gaussian eqn in terms of x? i need to calculate the x and y values. let x0=0 and y0=0. is it complex?

I'm trying to plot out the trajectory of an object in a program that is looping through the function and spitting out the x and y coordinates, but I'm having trouble. I want to see a parabola starting at 0,0 going up and ending again at x,0. Basic question: (units aren't critical here f/s m/s...

Please Help, I am not an mechanical engineer but am trying to learn Finite Element Methods to solve a 2D Steady State Heat Conductivity problem. Can anyone point me to an exact solution to the 2D Heat conductivity problem? Please be gentle, I have not had a physics class since 8th grade...

Homework Statement The problem is to obtain the inverse Fourier transform of the following 2D functions F(\mathbf{k})=\frac{k_{x}k_{y}}{k^{2}} Homework Equations The relevant equations are the 2d Fourier transform formulas described...

What I need is a 2d mesh,user specified.I have find some solutions on net but still have problems compiling.Anyone knows wheret o find more?

I need a formula that yields the speed and angle after a 2D collision that uses the coefficient of restitution (e). Preferably this would also be relativistic. I have searched EVERYWHERE for this and could not find it. To "prove" that I have indeed tried I have read the collision sections of...

Homework Statement The steady state temperature distribution, T(x,y), in a flat metal sheet obeys the partial differential equation: \frac{\partial^2{T}}{\partial{x}^2}+{\frac{\partial^2{T}}{\partial{y}^2}}=0 Separate the variables and find T everywhere on a square flat plate of sides S with...

Hi to all! I need to solve following equation: \frac{\partial^2 u}{\partial t^2} + 2 \beta \frac{\partial u}{\partial t} -c^2\nabla^2u=0 It describes a damped wave on a x-y plane. 2\beta is damping factor and c is wave speed. I haven't had any luck finding a PDE class that looks...

I want to make a matrix of values as so: F(0,0) . . . F(1,n) . . . F(n,1) . . . F(n,n) I could of course do it like this list=[] for i in range(0,n): for j in range(0,n): list.append(F(i,j)) a=array(list) a.reshape(n,n) But I am curious if there is a more...

Dear all, Anyone can tell me about the algorithm to write a simple CFD code to solve a flow problem.starting from grid gen, solver,post results. pls refer some site providing sample codes.

Hi, I like to start writing 2d CFD code for laminar flow using SIMPLER algorithm using c. help me from where i get information abt grid generation methods and GUI. If anyone had written such codes can guide me.

Hi, I stumbled upon this dilemma in a homework problem which involved 2D photon gas (unphysical, I know). How many polarization states are there for EM-radiation confined to 2D? In 3D it's 2, but how does it work in 2D? An EM-wave propagating in the z-direction can have its E-component...

Homework Statement Object A has a mass of 2.0 kg and an initial velocity of 2.5 m/s. It strikes Object B, which is at rest and has a mass of 2.0 kg as well. After the collision, the objects travel in different directions, with Object B traveling at an angle of 44 degrees from its...

Homework Statement Two radio frequency sources broadcast waves of the same frequency. They are placed 1.0 m apart. Let the x-axis be the line from one source to the other, and let x = 0 be at one of the sources. Nodes are observed at x = 0.24 m, x = 0.49 m, x = 0.74 m. 1) What is the...

Homework Statement This is for my mechanics class. It seems like it should be easier than I'm making it. A single object of mass m is attached to the ends of two identical, very long springs of spring constant k. One spring is lined up on the x-axis; the other on the y-axis. Chpose your...