1d Definition and 417 Threads

Homework Statement a rock is thrown nearly vertical upward from the edge of a tall building of height H. it just misses the edge of the building on the way down and strikes the ground T seconds after being thrown. given H, T determine the initial velocity of the rock the max height it reaches...

Homework Statement at the instant the traffic light turns green, s starts from rest and accels at a_s. at the same time k passes s with constant velocity v_k. given a_s, v_k, find distance before the cross again time it takes to do so velocity of s at this point plot the position as...

I am interested in the following random walk scenario, where a walker starts at a defined position greater than 0, say A, and then makes a "decision" to walk to either walk "b steps to the right" or walk "c steps to the left." He will choose the first option with probability p, and the second...

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...

Homework Statement Give example of a motion where x>0, v<0, a>0 at a particular instant. x-->Position v-->Velocity a-->Acceleration Homework Equations I thought I had to give an example such as a car, ball etc. But the answer says: x(t) ie; position for time t; given by...

Here in the 3d world, we have 2d paper where we can draw 2d representations of 3d objects. How would a 2d being draw a representation of a 2d object on a line? Is that even possible?

In a metallic system, the Fermi level is crossed either from the conducting zone into the non-conducting zone or vice versa. Is there an interpretation one can give to the direction of the crossing? In other words, if the 1D band gap diagram shows the fermi line is crossed from the...

Hi guys I am new here. I was asked by my professor a problem: a positron-electron pair is produced at the leftmost position of a 1D circular loop of radius R. e+ moves along the bottom hemisphere and e- moves along the upper one. They are confined in the circular loop and perform circular...

hi can anyone teach me how to put Mur's ABC in my fortran code for 1d fdtd maxwell's equation as below !1d fdtd Simulation in free space subroutine fd1d01(f0,miu,delta,S,E0) implicit none double precision :: f0 !frequency double precision...

Homework Statement ψx is the function of postion for a particle inside a 1D finite square well. Write down the expression for finding the particle a≤x≤b. Do not assume that ψx is normalised. Homework Equations The Attempt at a Solution This is to check I'm not going insane: P...

I have 2D elements distributed in a space of [-4, +4] and want to convert any point in the 2D space to a 1D real-valued number 0~1.0 such that 1st quadrant [+, +] should have higher values (importance) suppose 0.4~1 , 2nd and 3rd quadrant [+, -] and [-, +] should be next 0.2~0.4, and the 4th...

Say you have a furnace wall at a temperature at 400 degrees C and you have oven gas at 200 degrees C and you place an copper rod into the furnace. The copper rod has an initial temperature of 25 degrees C and a length of 1 meter and a diameter of 2cm. You want to find what find the time it takes...

Homework Statement to compute 1d fdtd maxwell equation using yee algorithm with fortran 90Homework Equations 1D discretization for maxwell equation (TEM mode) : electric field vector: Ez(i-1/2,n+1/2) = Ca*(Ez(i-1/2,n-1/2) + Cb(Hy(i,n)-Hy(i-1,n) magnetic field Hy(i,n+1) = Da*(Hy(i,n) +...

Homework Statement You are told that, at the known positions x_{1} and x_{2}, an oscillating mass m has speed v_{1} and v_{2}. What are the amplitude and angular frequency of the oscillations? Homework Equations x(t) = Acos(wt - \delta) v(t) = -Awsin(wt -\delta) w =...

Homework Statement The deuterium nucleus (a bound state of a proton and a neutron) has one bound state. The force acting between a proton and a neutron has a strong repulsive component of range 0.4 fm and an attractive component of range ~2.4 fm. The energy needed to separate the neutron from...

Homework Statement Solve the Laplace equation in one dimension (x, i.e. (∂^2h)/(∂x^2)= 0) Boundary conditions are as follows: h= 1m @ x=0m h= 13m @ x=10m For 0≤x≤5 K1= 6ms^-1 For 5≤x≤10 K2 = 3ms^-1 What is the head at x = 3, x = 5, and x = 8? What is the Darcy velocity...

i am trying to spproximate a PDE in the form below using the lax wendroff 2 step method in MATLAB coding: [h ; hu ] = [ hu ; hu^2 + 1/2gh^2] = [0; -ghbz] (where bz will equal zero) i believe this is then the case d(h)/dt + d(hu)/dx = 0 and d(hu)/dt + d(hu^2 + 1/2gh^2)/dx = 0 as...

In 3 space dimensions consider a 1D string under tension between two fixed points. Let the string lie at rest on the z axis between z = 0 and z = ∞. We can produce linearly polarized and circularly polarized waves if I move the end of the string properly? Now if we add an extra space dimension...

If we take a 1D uniform lattice I understand that we can derive a difference equation after using Hookes law and Newtons 2nd law as seen in the section labelled (Scalar wave equation in one space dimension, Derivation of the wave equation, From Hooke's law) in the link below...

If a particle of mass moves in a One-Dimensional harmonic oscillating potential, and the particle is in the first excited state, what will it's wave function look like? And the significance of it being in the first excited state versus the ground state? Thanks for the input!

Hi, I'd be most grateful for any help regarding the following problem: Consider a 1D crystal with 2 atoms in a primitive cell (let's call them atoms A and B). Each atom has only one valence orbital denoted as \left|\psi_A(n)\right> and \left|\psi_B(n)\right> respectively. Show that the...

Hello, I have Navier stokes in 1D \rho\left(\frac{\partial u}{\partial t}+u\frac{\partial u}{\partial x}\right)=-\frac{\partial p}{\partial x}+\mu\frac{\partial^2u}{\partial x^2} Condition of imcompressibility gives \frac{\partial u}{\partial x}=0 So I have Navier stokes...

Suppose we were to simulate 1D QED on a 1D lattice. How much information do we need at each lattice site given the mass, charge, and spin of the particles (does spin make sense in 1-1D spacetime?)? The links between lattice sites represent the gauge field? How much information is needed at...

In atom spectrum, such as for hydrogen, there are states of 1s, 2s, 2p, 3s, 3p, 3d, etc. There are no 1p, 1d or 2d, 2f. Simply because n= n_r + L +1. So the maximum of L is n-1. But when I read articles talk about meson, they list meson states of 1p, 1d, 1f, etc. Such as in the article “Quark...

My quantum text, leading up to the connection formulas for WKB and the Bohr-Sommerfeld quantization condition states that for \begin{align}u'' + c x^n u = 0 \end{align} one finds that one solution is \begin{align}u &= A \sqrt{\eta k} J_{\pm m}(\eta) \\ m &= \frac{1}{{n + 2}} \\ k^2 &=...

Ψ(x,t)=A⋅exp(A|x|)⋅exp(−iωt) Consider the one-dimensional, time-dependent wave function for infinite motion: (x,t) = Ae–a|x| e–it where A, a, and  are positive real constants. What are: (a) normalization constant A, (b) the quantum-mechanical expectation value of coordinate x...

Please help. My professor thinks I know this ****. Ψ(x,t)=Ae^-a(mx^2/η+it) A particle of mass m is in the infinite, one-dimensional, time-dependent state: where A and a are positive real constants. What are: (a) normalization constant A, (b) the potential energy function, U(x)...

Hi, There are three variables ax, ay and az, my question is: How to simplify the mean value <(ax^2+ay^2+az^2)^(1/2)> to <|ax|> ? What assumptions are required during the simplification? The statistical property of ax, ay and az is <ax^2>=<ay^2>=<az^2>. The assumption of the propability...

Expansion 1D Euler Eq.?? Trying to figure out an expansion step for 1D Euler Equations for unsteady gas flow. Continuity: \frac{\partial(\rho F)}{\partial t}+\frac{\partial (\rho uF)}{\partial x}=0 After Expansion: \frac{\partial(\rho)}{\partial t}+\frac{\partial (\rho u)}{\partial...

D'Alembert's solution to the wave equation is u(x,t) = \frac{1}{2}(\phi(x+ct) + \phi(x-ct)) + \frac{1}{2c}\int_{x-ct}^{x+ct} \psi(\xi)d\xi where \phi(x) = u(x,0) and \psi(x) = u_t (x,0). I'm trying to understand this intuitively. The first term I get: a function like f = 0 (x/=0), = a (x=0)...

Hello forum, I have a question regarding the delta function potential well. Given the following potential: V(x) = -αδ(x) for -a/2 < x < a/2 (α- positive constant) and V(x) = 0 elsewhere, how would one show that the ground state is the only eigenstate with E <0. One could of course solve the...

Short Version: It's been several years since I last practiced any mathematics or physics. I'm trying to get my mind as sharp as it was back then. I'm sure the solution is obvious, and just under my nose... I remember: P = P' + V't + (at^2)/2 Where P is position, P' is initial position, V'...

So I was sitting on the train last weekend, reading through my physics book on mechanical work and its relation to kinetic energy. One example would be that a box on a frictionless table being pushed and they would conclude that W = ΔK = ½mΔv2. Looking at this equation got me thinking...

In the problem I am suppose to use the wave equation to solve it. I assume 1D plane wave duct, u(x,t) = 1/(rho*C)*real((Aexp(ikx)-Bexp(-ikx))exp(iwt)) where C is the speed of sound, u is the velocity, p is the pressure, w is the angular frequency, t is time, rho is the density, and both...

Hi, I seem to have forgotten some of my math how-to, as I haven't done this in a while. Looking through my notes, Bird, Stewart and Lightfoot, Greenberg, etc. don't really help. My equation is this, at steady state: 0 = 1/r^2 ∂/∂r (D*r^2 ∂C/∂r) + P Where P is some production rate...

Homework Statement A rubber ball is shot straight up from the ground with speed vo. Simultaneously, a second rubber ball at height h directly above the first ball is dropped from rest. At what height above the ground do the balls collide? Your answer will be a symbolic expressions in terms...

Hi. I want to write the entropy of a 1d harmonic oscillator as a function of energy, but for each energy there is only one possible configuration. So is the entropy zero? I mean, the energy is E=hw(n+1/2), so there is only one microstate for each energy.

I have a 1_D diffusion equation dc/dt = D*d^2c/dx^2-Lc where L,D = constants I am trying to solve the equation above by following b.c. by FTCS scheme -D*dc/dx = J0*delta(t); where delta(t)= dirac delta function ----(upper boundary) I have written the code for it but i just...

Homework Statement Find the ground state (stable configuration at T = 0) of the one-dimensional ising model with first and second neighbour intercations: H = -J_1 \sum_{i} s_i s_{i+1} -J_2 \sum_{i} s_i s_{i+2} where s_i = \pm 1 The Attempt at a Solution I really don't know what i...

Homework Statement I have a 1D diffusion equation as du/dt = D*d^2u/dx^2-K*u; where D and k = constants the initial condition is u(t=0)=0 B.C. is u(x=0,t=0)= u0*delta(t); (a pulse like input at x=0 and delta(t)= dirac delta function) where u = contaminant in a semi infinite slab...

Homework Statement Two stones are thrown simultaneously, one straight upward from the base of a cliff and the other straight downward from the top of the cliff. The height of the cliff is 6.00m. The stones are thrown with the same speed of 9.00 m/s. Find the location (above the base of the...

Hi! I have calculated various eigenstate wavefunctions for a one-dimensional system of a particle in a potential. The potential is an even function. All the wavefunctions have become either even or odd functions which I understand why. The ground-state wavefunction has always been even, is...

Hi, I have written a numerical code to solve the 1D heat equation in cyclindrical coordinates: \frac{\partial T}{\partial t}=\kappa\left(\frac{\partial^{2}T}{\partial r^{2}}+\frac{1}{r}\frac{\partial T}{\partial r}\right) The problem I'm considering is a hollow cylinder in an infinite...

Hello, consider a 1D elastic wave which have the amplitude: A=cos(x) What is the energy density: \frac{dE}{dx} of this wave? I seem to recall that the energy of a wave is proportional to the square of the amplitude: E \propto A^2 That seem to mean that \frac{dE}{dx} \propto cos(x)^2...

Homework Statement Given a square well, Infinite wall at x=0 Wall height U for x>L For E<U, find solutions to the schrondinger equation inside the well, and beyond x>L which satisy boundary conditions for x=0 and x=\infty Taking conditions at x=L, find the allowable energies of the...

Hi guys, I'm working through past papers and I have a problem with deriving the renormalised scaling of the following: [PLAIN]http://dl.dropbox.com/u/16658950/helpme.JPG I'm doing the rescaling as I would for a 1D ising model decimated with l = 2 (so every other spin, but N=4 in this...

Hello! I'm having the following problem; [PLAIN]http://www.hot.ee/jaaniussikesed/probleem_graafik.jpg I try to plot a 1D matrice with a sequence, or a 1D matrice and I get a result that "this value must be real". Now... what!? I am using MathCAD 14. Help is much appreciated, Uku

Homework Statement A bare slab fuel element is 0.2 in thick. It has a kf = 10 Btu/(hr*ft*F) and a q''' = 5e7 Btu/(hr*ft^3). At x=0 (left hand face), h_lhs = 400 Btu/(hr*ft^2*F) with a fluid temp of 700F. At x=0.2 in (right hand face) the heat transfer coefficient is h_rhs = 300 Btu/(hr*ft*F)...

Homework Statement Consider phonons propagating on a one-dimensional chain of N identical atoms of mass M interacting by nearest-neighbour spring constants of magnitude C. Show that the Debye frequency can be written as w_{D}=\pi \left(\frac{C}{M}\right)^{1/2}. Homework Equations The...

Homework Statement Q: Two air track gliders of masses 300g, and 200g move towards each other in opposite directions with speeds of 50cm/s and 100cm/s respectively. Take the direction of the more massive glider as positive. If the collision is elastic, find the velocity of each glider AFTER...