2d Definition and 1000 Threads

Homework Statement The problem is stated here (from brilliant.org) http://i.imgur.com/MkWwnjT.png Homework Equations momentum = mass * velocityThe Attempt at a Solution My attempt at a solution can be found here: http://i.imgur.com/Zsco86W.jpg I get the answer 0.035kg, but that is not an...

Homework Statement A string is sewn in a 2D membrane. What is the amplitude of the reflected wave? All the parameters you need in order to get to the result are known. Homework EquationsThe Attempt at a Solution Ok, so we have a 2D membrane, with a string at ##x=0## along the the ##y## axis...

I've formulated a method for modeling the flight of a rocket projectile. Can anyone read it over and point out any mistakes false assumptions, etc? thanks!

Homework Statement Find stationary state of a circular membrane, on which a coin is put. Homework EquationsThe Attempt at a Solution I am not sure about the second boundary condition, so if any of you has the time, please check the following solution: $$u_{tt}=c^2\nabla ^2u+\rho g$$ Where...

Hi everyone, I am a graduate student in psychology and am working on a research project where I am trying to derive the kinematics of a mouse tracking task. I am currently writing a MATLAB script to do this, and I believe my equations for velocity and acceleration are correct, but I have very...

Homework Statement A 2.0 kg ball moving with a speed of 3.0 m/s hits, elastically, an identical stationary ball as shown. If the first ball moves away with angle 30 ° to the original path, determine a. the speed of the first ball after the collision. b. the speed and direction of the second...

Hi guys! I'm new to the forum, i hope you can help me with this trouble! it really is important =D i have a 2D binary compound AB (made of one of the 100 family of planes of a rocksalt structure) and i am asked to "consider a single s-orbital on each atom (atomic energies Ea,Eb) and nearest...

Homework Statement This is not a homework problem per se, but I have been working on it for a few days, and cannot make the logical connection, so here it is: -- The problem is to show that ##\frac{1}{4\pi} \int_{-\infty}^{\infty} \frac{ e^{-\sqrt{\xi ^2 + \alpha^2 } |y-y'| + i \xi (x-x')...

A skier 58.0kg coasts down a 25.0 degree uniform slope. A kinetic frictional force of 70.0N opposes her motion. At the top of the slope her speed is 3.60 m/s. What is her final speed at a distance 57.0 metres down the slope? Kinetic Energy = 1/2mv^2 V=Vi+at^2 F=ma So far I decomposed the...

Homework Statement Consider the following real scalar field in two dimensions: S = \int d^2 x ( \frac{1}{2} \partial_\mu \phi \partial^\mu \phi - \frac{1}{2} m^2 \phi^2 - g \phi^3) What are the Feynman rules for calculating < \Omega | T(\phi_1 ... \phi_n ) | \Omega > 2. Homework...

plane wave is represented as exp (ik.r) and the cylindrical wave as 1/sqrt(r) *exp(ik.r) and the spherical wave as 1/r*exp(ik.r) Have anyone tried to plot these waves? How to do it? Attempt: in Matlab assuming k=1 >> x=linspace(-1,1,100); >> for(ii=1:100) fp(ii)=exp(i*x(ii)); end >>...

Sorry for the confusing tittle but I could not explain it better. Here is what I am trying to ask: When you have 2 axis(x and y) such as the image below, the sum of the two angles, a and b will always be equal to 90 degrees. a + b = 90degrees However when you add a 3rd axis(x, y and z, making...

In adobe photoshop, is it possible to take and wrap a 2D texture onto a 3D model? And is it also possible to make a 2D object from a photo into a 3D one?

Now plasma represents collective wave-like motions of charged particles. In 3D, their frequency is well known to be almost a constant, ##\omega^{3D}_p \approx \sqrt{4\pi ne^2/m}## with n=charge density, m=particle mass. However, in 2D, one can show that it becomes ##\omega^{2D}_p \sim...

Homework Statement A catapult projects a stone in the normal direction to a playground which slopes at a angle of 10 degrees to the horizontal. The initial speed of the stone is 18 m/s. calculate the range parallel to the playground. Homework Equations the usual ones! The Attempt at a...

Homework Statement A two dimensional solid has two electrons per unit cell and has a Bravais lattice with primitive vectors ##\vec a = \ell \hat x## and ##\vec b = \ell \hat y##. The crystal potential is weak and the solid behaves like a free electron metal. a)In a reciprocal space diagram...

I'm recently new to the field of 2D Fourier Transform Infrared Spectroscopy and am learning its applications. I would like to know its applications in biology. Specifically, is there anything in the 400 nm to 1000 nm range that is important in protein structure, protein dynamics or biology in...

Homework Statement charge e is within 2 dimensions in presence of magnetic field. H = 1/2m (p - e/c A)^2 A = 1/2* B x r p and r have two components Show: H in terms of B along z axis resembles 2D HO (with some extra term) express H in terms of x, y, p_x, L_y Homework Equations L = r x...

I need some information urgently. I am working on crack of a 2-D cantilever beam. One side of the beam is fixed. I am applying a sinusoidal time varying load on other end in Y-direction.Beam length and width are 100cm and 10cm respectively. crack is 05 cm in y-direction. I have attached data and...

Problem statement: Two pucks of radius 0.05 meters collide as shown in attached picture. The mass of puck 1 is 0.1 kg and that of puck 2 is 0.15 kg. The initial velocities are v1i = 1 m/s and v2i= 0.6 m/s. (1) Assuming no friction between the pucks, only normal forces during collision, in...

Homework Statement I have to come up with a program that calculates the nodal temperatures of a sheet with a slot with 2D conduction. Due to symmetry the shape can be reduced to an L shape. Matlab and loops have always given me trouble, so I tried the Interactive Heat Transfer 4.0...

The spectral radiance of a blackbody has units of W·sr-1·m-2·Hz-1. How do I deal with these units if I want to think about a 2D problem of radiation in Cartesian coordinates? I assume that instead of a sphere of emission (which would result in artificial decrease in intensity with the inverse...

Hello friends, I am new for numerical methods and programming. i have been trying to devolop a program in 2D poisson heat equation in cylinder (r,angle) by finite difference method ∂2u/∂r2 + 1/r * ∂u/∂r + 1/r2 * ∂2u/∂θ2 = Q(u,θ)discritized equation :- ui+1,j − 2uij + ui−1,j/(∆r)2 + 1/ri *...

Homework Statement Two balls A and B simultaneously start to roll down without friction along two different chords of a circle as shown in the figure. Find which ball will hit the circle first? (image attached) 2. The attempt at a solution I have divided the velocity of the balls into vector...

It can be easily proved that Bose Einstein condensation can be got in infinite 2D. But what about finite 2D with extreme large "Volume" L^2 ?

http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas Simpson rule: 1 4 1, and the composite version: 1 4 2 4 2 4 2 4 ...4 1 in a double integral we just compute rows, and next columns, a this gives a matrix: http://mathfaculty.fullerton.edu/mathews/n2003/SimpsonsRule2DMod.html Milne's...

Suppose, I know the metric tensor of a 2D space. for example, the metric tensor of a sphere of radius R, gij = ##\begin{pmatrix} R^2 & 0 \\ 0 & R^2\cdot sin^2\theta \end{pmatrix}## ,and I just know the metric tensor, but don't know that it is of a sphere. Now I want to draw a 2D space(surface)...

Homework Statement A stone is thrown at an angle of 36.9 above the horizontal at 24.0 m/s from a building 56m high. What is the maximum height (with respect to the ground) that the stone reaches? Homework Equations - The Attempt at a Solution No clue. Have a picture drawn and all my knowns...

Homework Statement How do you calculate compute the the magnitude of the total force of three charges and also the angle it makes with the x-axis? Knowing the magnitude and also the 2d co ordinates of the charges. (x1,y1) (x2,y2) (x3,y3) I know for definite I use the below calculation but...

I can't compute the integral: \int \frac{\arccos(\sqrt{x^2+y^2})}{\sqrt{x^2+y^2}}\frac{x-a}/{(\sqrt{(x-1)^2+y^2})^3 dxdy on an unit circle: r < 1. for const: a = 0.01, 0.02, ect. up to 1 or 2. I used a polar coordinates, but the values jump dramatically in some places (around the 'a' values)...

Hello everybody. Although this is just a kinematics problem, I am having a hard time figuring out what to do. The question is: An archer on the planet zorg spots an octomorph that is resting in a tree above water. The octomorph's position in the tree is 100m away horizontally and 100m...

Homework Statement (a) the density of k-states g(k) = L^2*k/2*Pi. (b) the density of states g(E) = L^2*m/Pi*h^2 (c)The density of states per area n2D(E)=m*/Pi*h^2 (d) Sketch a graph of n2D(E) vs E. (e) Calculate n2D(E) as a quantity. The questions don't have to be answered in full a...

Given a warren truss, where the load is 2kN/m so the weight per joint is 10kN, since the ends are supported by ground not truss, can anyone please verify my way of solving for the tension and compression at point B. See attachment Your help is greatly appreciated. So I figured out that AB is...

Homework Statement Standard pool balls have a mass of 0.17kg. Before a collision, ball A is at rest and ball B is traveling at 4.5 m/s [N]. After the collision, ball B is traveling at 1.6 m/s [N20E]. What is the velocity of ball A? Homework Equations pinitial = pfinal m1v1 + m2v2 = m1v1 + m2v2...

Hi friends, i have developed an code for a non linear heat conduction in 2 dimensions with dirichlet boundary condition by finite difference method in Matlab. my code is running slow to give output. If anybody has any idea of solving this equation or have written any Code for this equation...

Hi. Can you do a computer simulation of a membrane with a standing wave(s)/node(s) with a shape of a cube or cone? It is possible on a string so why not on a membrane. Can you do a computer simulation of a spherical membrane with a standing wave(s)/node(s) with a shape of a cube or cone...

Homework Statement Firing something at 40m/s at angle X, it lands 65meters away, give 2 angles it could be.. (Assume g=10m/s^2)(Fired at y=0)(No air resistance) Homework Equations D = v^2/g sin(2x) [/B] The Attempt at a Solution d= v^2/g sin(2x) 65 = 40^2/10 sin(2x) 650/1600 = sin(2x)...

I'm struggling to do this problem. "When Babe Ruth hit a homer over the 7.0m -high right-field fence 120m from home plate, roughly what was the minimum speed of the ball when it left the bat? Assume the ball was hit 1.0m above the ground and its path initially made a 30∘ angle with the ground."...

Homework Statement Suppose \mathbf{u,v,w} \in {\rm I\!R}^2 are noncollinear points, and let \mathbf{x} \in {\rm I\!R}^2. Show that we can write \mathbf{x} uniquely in the form \mathbf{x} = r\mathbf{u} + s\mathbf{v} + t\mathbf{w}, where r + s + t = 1. Homework Equations Suppose \mathbf{a,b}...

Hello everyone, I would like to get ~200 MeV quasi-monoenergetic electron beam by doing 2D Particle-In-Cell simulation in bubble regime. The moving window dimension is 50x50 μm for x and y, the simulation mesh size is set 0.04x0.4 μm, each mesh includes 10 particles, laser wavelength is 800 nm...

For an image, higher the dimensions of image ,more is the resolution of the image.But is there any relation present between sampling frequency and dimensions of image? Also, Whether the Number of samples presents in an image is equal to product of dimensions of image?

Homework Statement The truck is to be towed using two ropes. If the resultant force is to be 910N directed along the positive x axis, determine the magnitudes of force F1 and F2 acting on each rope and the angle θ of F2 so that the magnitude of F2 is a minimum. F1 acts at 20° from the...

Homework Statement A large very powerful gun shoots a bullet that easily goes through a block. In the process the block is knocked off the post and falls to the ground. Which hits the ground first, the bullet or the block. Why? Homework Equations The Attempt at a Solution I am...

I was recently trying to test something out with the Riemann tensor. I used only 2 dimensions for simplicity sake. As I was deriving the Riemann tensor, I noticed that it looked as if all of the elements were going to come out to be 0 (which they all did). Therefore, this coordinate system is...

Homework Statement Let a particle of mass m moving in 2d space in a potential V (x, y) = -1/2 kx2 + 1/2 λ0 x2y2 + 1/4λ1x where k,λ0,λ1 > 0.At what point (x0, y0) is the particle in stable equilibrium? 2 marks Homework Equations ∂V/∂x=0 ∂V/∂y=0; ∂2V/∂x2 > 0;∂2V/ ∂y2 > 0 The...

So I have a boat going across a river (y-direction, north) 400m wide. I am trying to hit a target 75m in the positive x direction on the opposite side of the river. My boat will travel a velocity v. The river will provide a constant velocity of +0.5 (east) I am trying to find the angle a, north...

Hi all This question came up to me when I was playing a game called KSP (a space sim game): Given an initial velocity and starting altitude, how do you create a 2D Cartesian equation of the orbit of that projectile around earth? For example if I told you a projectile is traveling at a...

Is this a correct derivation of a relation between displacement of a particle with its terminal launch angle, velocity, and environmental gravity? Let the velocity of the projectile be denoted V_n. Let the terminal side of the launch angle with respect to the ground be denoted \theta. The...

You can use transfer matrix method for 2d Ising model. Is there a list of models for which this method could be of use. Such as classical Heisenberg perhaps? Or Potts?

Hello Forum, The 1D harmonic oscillator is an important model of a system that oscillates periodically and sinusoidally about its equilibrium position. The restoring force is linear. There is only one mode with one single frequency omega_0 (which is the resonant frequency). What about the...