1d Definition and 417 Threads

I'm learning c++ and currently trying to write a little programme for 1D linear convection (wave equation). I have managed set all boundary and initial conditions as well as a mesh. But I have reached the point where I can't understand why the program does what it does. In red I...

I'm doing a project on a vibrating guitar string and I have completed all the simulation and experimental work, but I do not fully understand the theory behind it. I need to derive the 1 dimensional case of the wave equation, as the 1 dimensional case is considered to be the most convenient...

Homework Statement An infinitely deep one-dimensional potential well has a width of 1 nm and contains 10 electrons. The system of electrons has the minimum total energy possible. What is the least energy, in eV, a photon must have in order to excite a ground-state electron in this system to the...

Homework Statement A 50.0-g superball is traveling at 25.0 m/s bounces off a brick wall and rebounds at 22.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 3.50 ms (.0035 s) what is the magnitude of the average acceleration of the ball during this time...

Hey! I have some dumb-smart question Does 1D line have physical width? My logic says that mathematically you can go smaller and smaller,but I see there being a problem with 1D having infinitly small width in physics. If 2D object has infinitly many 1D lines that would suggest that 2D...

Homework Statement See figure attached for problem statement. Homework Equations The Attempt at a Solution Here's as far as I got, The part that confuses me is the range we should solve this equation. It says, \text{from } t=0 \text{ to } 1d I put the ^{-1} in...

Consider mass m_{1}and m_{2}with position vector (from an inertial frame) \overrightarrow{x_{1}} and \overrightarrow{x_{2}} respectively and distance between them be x_{0}. m_{1}\frac{d^{2}}{dt^{2}}\overrightarrow{x_{1}}=\overrightarrow{F} \Rightarrow...

All, I am reviewing for a comprehensive exam and am extremely weak on 1D Motion. Can you please help me out? A lab cart travels along the x-axis and its position as a function of time is given by the following expression: x(t)= 6m - (8 m/s)t + (1 m/s2)t2 1. Displacement of cart during time...

Homework Statement The question I have a one-dimensional linear spring with spring constant E. The tension is given by σ = Eε, epsilon = strain.. The left side of the spring is held fixed, the right side has a mass m attached to it. We can neglect gravity. What is the natural oscillation...

Homework Statement A particle moving on a straight line is subject to a resistive force of the magnitude kv^n, where v is the velocity at time t and k is a positive real constant. Find the times and distances at which the particle comes to rest i.e. v=0, for the following cases (this assumes...

How would I come up with an equation (in one dimention), for the airy pattern of a telescope with a given diameter observing at a given wavelength? something that looks like this http://upload.wikimedia.org/wikipedia/commons/9/93/Airy_Pattern.svg I want to be able to plot Intensity in the...

Homework Statement Equation for a particle moving in one dimension with potential energy U(x): t=\int1/\sqrt{2(E-U(x))/m} , integrated from x0 to 5x0 Suppose U(x)=c/x for x>0. Calculate the time for the particle to move from x0 to 5x0, starting from rest at x0. Leave the answer in...

Homework Statement On June 14th, 2005, Asafa Powell of Jamaica set a world's record for the 100-m dash with a time t=9.77s. Assuming he reached his maximum speed in 3.00s, and then maintained that speed until the finish, estimate his acceleration during the first 3.00s. Homework Equations...

1. A parachustist jumps from an airplane and freely falls y=49.4 m before opening his parachute. Thereafter, he decelerates at a=2.02 m/s2. As he reaches the ground, his speed is 3.11 m/s. How long was the parachutist in the air? For this one I managed to get the solution already using a method...

Hello, I am trying to accurately simulate motion in 1D with a jerk that is changing non-linearly, but predictably. As an arbitrary example, picture jerk increasing logarithmically over time. This is being done in the context of a physics simulation that is 'stepping' frame-by-frame (ie 60...

Hi, I'm currently working through some exam papers from previous years before an upcoming module in Quantum Mechanics. Homework Statement See the attached image Homework Equations The Attempt at a Solution I'm a little stumped with this one, I'm assuming that I'm looking...

Hi, I'm currently working through some exam papers from previous years before an upcoming module in Quantum Mechanics. I'm a little stumped with this one, I'm assuming that I'm looking at a 1D harmonic Oscillator and the wording of the question suggests that the wave function just needs to be...

Homework Statement To save fuel, some truck drivers try to maintain a constant speed when possible. A truck traveling at 91.0 km/hr approaches a car stopped at the red light. When the truck is 115.7 meters from the car the light turns green and the car immediately begins to accelerate at...

Hi, I have the following problem. I am tried to numerically solve the 1D heat equation for a metal bar of length L. Using the forward time, centered space equation a(t+1) = a(t)+(alpha*deltaA/(deltaX)^2)*(a(x+1,t)-2*a(x,t)+a(x-1,t)) The problem is that I only have ONE heat source at...

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 5.85 m. The stones are thrown with the same speed of 8.59 m/s. Find the location (above the base of the...

Homework Statement An electron in a one dimensional crystal is bound by: U(x) = \frac{-\overline{h}^{2}x^{2}}{mL^{2}\left(L^{2}-x^{2}\right)} for \left|x\right| < L and x = infinity for \left|x\right| \geq L Show that a stationary state for the electron in the potential well \psi(x) =...

Let's suppose that we have two point particles with masses m1,m2 and the spherical shell with mass M, placed in a line, at distances h1,h2 and H from 0 in that line (0 is the center of some inertial frame of reference). The initial conditions and the equations of motion are the following...

Let's suppose that we have two point particles with masses m1,m2 and the spherical shell with mass M, placed in a line, at distances h1,h2 and H from 0 in that line (0 is the center of some inertial frame of reference). The initial conditions and the equations of motion are the following...

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?

I am trying to write a solver for a 1D wave equation in MATLAB, and I have run into interesting problem that I just can't find a way out of. I start with the wave equation, and then discretize it, to arrive at the following, U{n+1}(j)=a*(U{n}(j+1)-2*U{n}(j)+U{n}(j-1))+2*U{n}(j)-U{n-1}(j)...

Homework Statement This is from an old exam I'm studying from. It goes: "A particle of mass m is traveling in one dimension under the influence of a potential V = -Fx where F is a known constant. Find the energy spectrum and wavefunctions. Hint: You may want to work in momentum...

Homework Statement Three charges lie along the x-axis. The positive charge q1 = 10.0 x 10^-6 C is at x = 1.00 m, and the negative charge q2 = -2.00 x 10^-6 C is at the origin. Where must a positive charge q3 be placed on the x-axis so that the resultant force on it is zero? Homework...

I'm trying to understand how to set up the problem of a 1D wire that is insulated at one end and has a heat source at the other. I know the heat law, from my textbook: du/dt = B d2u/dx2 + q(x,t) 0 < x < L, t > 0 Where q(x,t) is the source of heat. The problem is, I want the heat...

Homework Statement I have been asked to model the flow of a slightly compressible liquid through a rigid, incompressible porous medium in 1D, assuming the flow obeys Darcy's law. I am given a rectangular prism of cross sectional area A with length L, a source of liquid (say water) on one...

QED in 3D --> QED in 1D, what changes? Can we have massive charged and massless fields which interact in one space dimension? What might the interaction term look like? Thanks for any help!

Friends, I am trying to consider an impurity which can be viewed as a 1D resonant-tunnelling problem. I gather that the transmission coefficients TL and TR will decay exponentially from the impurity to the edges of the barrier. However, I am unsure how to predict how the peak & area of T(E)...

1D Potential 1. Homework Statement Given: U(x) = U_0 - U_n*e^-(kx^2), U_0, U_n and k are all constant. i) What is the maximum E for the particle to remain in potential? ii) Show that the potential has a minimum at x = 0. iii) If a particle of mass m is placed near the minimum at x = 0, and...

Problem: Three friends do a 1D Random Walk with p=q starting at 0. Are they guaranteed to all meet again somewhere? So all the friends are starting at 0 at the same time and we want to know if they are guaranteed to meet again anywhere in the walk. Hint: if they do meet, which places are...

Hello, I am trying to solve a 1D heat analysis problem for an electric generator. The stator or the device icludes the copper which is well insulated and is cooled from the left using water running through a pipe. The rotor is made of magnets supported by an iron frame. Cooling air is blown...

Hi, I have a pseudocode I would like to try and implement and understand the programming of it in python. The physics and maths of the case is no problem, but the implementation of the code in Python is something I'm not familiar with. The problem is a simple 1D linear convection using...

Ok, so I am trying understand how to derive the following version of the Schrodinger Equation for QHO: \frac{d^2u}{dz^2} + (2\epsilon-z^2)u=0 where \ 1. z=(\frac{m\omega}{hbar})^{1/2}x and \ 2. \epsilon= \frac{E}{hbar\omega} I've started with the TISE, used a potential of...

Hello, I am reading a book about finite elements with regards to stress analysis. I'm pretty sure the book is full of mistakes, which makes following and doing the examples fairly difficult. I have posted a 1D analysis from the book, I'm not even sure how he comes up with some of the numbers in...

1D advection-diffusion--need to check my code; any suggestions? Hi everyone: I am teaching myself transport/programming, and have created a simple program for 1-D advection-diffusion (constant velocity, diffusion coefficient, central differencing, Crank-Nicolson). I would like to check...

Hello--- I am reading a paper which presents a method to determine attenuation (and Q factors) from reflection seismic data (Y. Wang, "Q analysis on reflection seismic data," Geophysical Research Letters, Vol. 31, 2004). To perform signal processing on a seismic trace, the paper describes...

Hi all, I was wondering whether there was any work done on a random walker on a 1D lattice with diffusing boundaries? Any links or suggestions would be great!

Homework Statement Two identical positive charges of +Q are 1 m apart. What is the magnitude and direction of the electric field at point A, 0.25 m to the right of the left-hand charge? Homework Equations E = kQ/r^2 The Attempt at a Solution I summed up kQ+/(.25^2) and...

So in one of my classes, we very non-rigorously derived the 1D stress field for a bar with a longitudinal surface loading T(x) like show below: By taking out a differential element (assuming constant cross-sectional area) and applying good old Newton's Second, we end up with: A...

Hello all, This is to do with forced longitudinal vibration of a rod (bar). It's basically a problem to do with the linearised plane wave equation (1d). The rod is fixed firmly at one end, and excited at the other by a harmonic force. The wave equation (with constant rho/E instead of...

Homework Statement Two identical non-interacting spin 1/2 particles are in the one-dimensional simple harmonic oscillator potential V(x) = kx2/2. The particles are in the lowest-energy triplet state. a. Write down the normalized space part of the wave function. b. Calculate the energy of...

I Have a brief idea about the equation and i have searched the web for its application to one dimensional harmonic oscillator but no use. Any Help Would Be Welcomed Especially about the latter:smile:

Homework Statement Determine the probability of finding a particle in a 1-D box of size L in a region of size 0.01L at the locations x = 0, 0.25L, 0.5L, 0.75L and L when it is in its ground state. As percentages Homework Equations \Psi(x)=\sqrt{\frac{2}{L}}sin(\frac{nxPI}{L})...

Hi, I'm looking for a solution to u_t + A u_x + B (u - f) = 0 where f is a given function linear in x and constant in t. u(x,0) = f(x) u(0,t) = f(0) A and B constant. Does this equation have a name? It's almost the inviscid Burger, but has the damping term (B u) and force term...

Hi Most of my work in the past has been on 1D independent particle systems where I use matrix diagonalisation to solve the time-independent Schrodinger equation. How do I go about this for 2D? Or, more accurately, for a two-body wf in 1D? It strikes me as straightforward to construct a...

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Homework Statement A car making a 94-km journey travels 39 km/h for the first 47 km. How fast must it go during the second 47 km to average 51 km/h? Homework Equations The Attempt at a Solution