Method Definition and 1000 Threads

I need a way to generate cool air outside when temperatures are 90s and above. Basically what I am thinking of doing is essentially like positioning a fan right beside a bowl of ice cubes. Only in my case, instead of using ice cubes, an electrically powered cooling device that can slightly...

I know magnetic launch tracks on the side of mountains has been proposed before but what if... you vacuum the inside of the launch track on the side of the mountain and extend the tube up from about 5K meters to 30K meters? The tube on the side of the mountain would be made of a strong metal...

Max: 3x + 5y s.t. x + 2y ≤ 5 x ≤ 3 y ≤ 2 x,y ≥0 By the simplex method, the profit is $14. Using sensitivity analysis I changed the RHS of the 1st constraint and keeping everything else constant, I get the best profit value of $19 at RHS of 7. What other methods can I use such as the...

I'm talking about different bases here. I've heard a bunch of people say that base 12 is the best way to go, since it would make basic math easier. After all, 10 from the decimal system has only 4 factors (1,2,5,10), whereas 12 from the duodecimal system has 6 (1,2,3,4,6,12). But, looking from a...

There are 2 unknowns in the formula. The time period of rotation and the mass enclosed by orbit is Star. So how could we calculate the expected time period of rotation of stars in a galaxy and thus velocity of stars.

Why are potentiometers not a good method of speed control(in terms of energy)?

So, I found this method, I don't think I was the first to, though, but I don't see any post related to this anywhere on the internet, so maybe there's a slim chance I was the first? Anyway, it doesn't really matter. The method does not give the precise result, only approximations, but I find it...

Homework Statement Not sure if this belongs in the 'Advanced' section so apologies if it does not. I am using a monochromator to measure spectrum lines from a rubidium lamp. From the data (wavelength of spectral lines plus transition number 'n') I am asked to use a graphical method to...

I'm trying to understand the derivation for methods of Greens functions for PDEs but I can't get my head around some parts. I'm starting to feel comfortable with the method itself but I want to understand why it works. The thing I have problem with is quite crucial and it is the following: I...

Homework Statement Find the volume of the solid obtained by rotating y=x^2 and x = y^2 about y=2 Homework Equations V= 2πrh The Attempt at a Solution When I had constructed the graph I determined the following: r= 2-(y(1/2)) h= 1-y2 after converting V into an integral I applied fundamental...

Homework Statement Write a C program to simulate a falling object. The program should ask for the initial height of the object, in feet. The output of the program should be the time for the object to fall to the ground, and the impact velocity, in ft/s and miles/hour. Your program should use...

I´m simulating an induction motor control using DTC (direct torque control). I want to tune my PI controller to achieve a fast start up, but I don't have a transfer function to make an analysis. How can I set this controller?

Homework Statement Hello everyone, I am new here and have a question regarding method of images in my electricity and magnetism class. I need help to even get the ball rolling. The question is as follows: a) What is the image of a dipole, oriented toward the center of the conducting sphere, if...

Can the phase stationary method be applied to complex functions? And if it does, is it still called phase stationary method? I ask this because there are several methods for asymptotic analysis and I need to be sure if I can use this method for complex function. Is there any difference with the...

The paper Optimal Cloning of Pure States by R. F. Werner describes a method for approximately expanding an unknown state ##\rho## containing n copies of a qubit, so ##\rho = (\alpha \left| 0 \right\rangle + \beta \left| 1 \right\rangle)^{\otimes n}##, into a larger state with d more qubits...

Homework Statement So I have the following : AX=B, where $$A=\begin{bmatrix} a_{ij} \end{bmatrix}_{mXn}$$ with $$a_{ij}=i$$ $$ X=\begin{bmatrix} X_{1} &X_{2} &X_{3} &... &X_{n} \end{bmatrix}^T$$ and $$B=\begin{bmatrix} 1 &2 &3 &... &m \end{bmatrix}^T$$ Homework Equations Gauss'...

I am solving some 2nd order differential equations using the finite element method. Doing so I represent the second order derivative at a given point as: ∂2ψi/∂x2 = 1/(Δx)2 (ψi-1+ψi+1-2ψi) And solve the differential equation by setting up a matrix of N entries and solving for the eigenvectors...

I am doing a lab which involves the determination of vapour pressure of a particular compound by Knudsen Effusion. Like other analytical methods it involves calibration but we are using the know vapour pressure of naphthalene because its in the accepted range. So we have an equation for the...

Homework Statement Use the Heun method to compute the period of small oscillations about the equilibrium position of a nitrogen atom. xi = 1.1 Um = 7.37 x0 = 1.2 alpha = 2.287 m = 2.325e-26 Homework Equations [/B] U(x) = Um((1-e^(-alpha(x-x0)))^2 - 1) The Attempt at a Solution I was told to...

How do you get deflections of a fully restrained beam? :) I already solved for the propped reactions and end moments.. I'm not sure how to do that part. :/ ありがとうございます。 :)

Hello, I have already studied first year mathematics but I am doing some basic revision incase I missed anything, (I skipped two grades and am thus missing some small simple things I should know) When simplifying the single term expression, 2x^2y^2 times 5xy^4 my initial thought was they...

Please Tell how improve my physics concept in better way?

Homework Statement Find the voltage, V, across the 6A current source Homework Equations V=IR Node Voltage Method The Attempt at a Solution Did I set this up correctly to find my voltage?

Description of the Method We are given a trinomial of the form $ax^{2}+bx+c$, and asked to factor it into a product of two dissimilar binomials $(fx+u)(gx+v)$. The method that follows assumes $a,b,c$ have no common factor; if they do, you must factor out the greatest common factor before...

Prove both by method of contrapositive. 1. If a ≤ b + ε, where ε > 0, then b > a. 2. If 0 ≤ a - b < ε, where ε > 0, then a = b. I'll start with problem 1.: p: If a ≤ b + ε, where ε > 0 q: b > a neg q: b < a neg p: for some ε' > 0 1/2(a - b), a > b + ε' define ε' = 1/2(a - b) I...

The pole method of magnetostatics is presented in many E&M textbooks, particularly the older ones, to do computations in magnetostatics and even to try to explain permanent magnets. An equation that arises in the pole method is B=H+4*pi*M (c.g.s. units), where H consists of contributions...

Is there anybody on the forum who is up to speed with the ins and outs of these devices? 99% of research papers and all manufacturers comment I have read say these devices are working because the distant object emits radiation that the detector absorbs and therefore this absorbed energy *heats*...

If there are any experimentalists out there maybe you could help? I need to bubble gas through a liquid at ~80 mL/min is there a specific instrument designed to do this? I'm assuming it's some sort of pump, what would it be called in a chemistry lab? Thank you for any suggestions / help.

Hermite's ODE is $y'' - 2xy' + 2\alpha y = 0$ Let $y = \sum_{\lambda = 0}^{\infty} {a}_{\lambda} x^{k+\lambda}, y' = \sum a_{\lambda} (k+\lambda)x^{k+\lambda-1}, y'' = \sum a_\lambda (k+\lambda)(k+\lambda-1)x^{k+\lambda-2}$ I get the indicial eqtn of k(k-1) = 0, therefore k = 0 or 1...

So, when you use the Frobenius method on a differential equation, you assume a solution Σa_k*x^(k+s). Sometimes you get more than one solution for s in the indicial equation. Is the sum of these two solutions you get from evaluating the rest of the problem with each s solution the...

Good Day Let's say I have developed a new method to extract, more efficiently (yes, "more efficiently" is ill-defined; but bear with me) the differential equations that describe a specific phenomena (please just assume it). So now I have a system of coupled second order differential...

In the chapter 9-5 "The Linear Variation Method" p. 363 from the book: Basic Principles and Techniques of Molecular Quantum Mechanics by Ralph Christoffersen, the first thing he does is to minimize the energy, E = c†Hc/c†Sc, by requiring its derivative with respect to the...

I'm solving a problem numerically where I have some charge density above an infinite, grounded conducting plane and want to determine the electrical potential at a given point. My intuition says that this is not simply given by the potential of the charge density above the plane, since this will...

I would like to know how to implement internal hinges in a program I'm developing. A hinge is created by changing the stiffness matrix of the beam. The problem is when two interconnected beams have a hinge at the same location, so basically we have a hinged joint, in this scenario I will obtain...

If we have a linear programming problem that is of the form as the following: $$\max (- x_1+ 2 x_2-3x_3) \\ x_1- \frac{1}{2} x_2+x_3+x_{4}=11 \\ 2x_2-x_3+x_5=0 \\ 2x_4+x_6=8 \\ x_i \geq 0, i \in \{ 1, \dots, 6 \}$$ we cannot use the simplex method since we cannot find a basic feasible...

Homework Statement What is the volume of a solid formed by the area trapped between y= -x^2 and y= -2x rotated 360° around x-axis? Homework Equations V = ∫A(x)dx The Attempt at a Solution y=y -x^2 = -2x x^2 -2x = 0 x(x-2) = 0 This means that the two functions cross at x = 0 and x = 2 From x...

I've written a poly phase merge sort using 3 "stacks" in C++. The key part of the logic is to merge from containers A and B into container C. It's expected for A or B to go empty with lots of data remaining on B or A. To deal with this, when A or B go empty, the empty container is swapped with C...

Homework Statement Solve \begin{equation*} 36x^2y''+(5-9x^2)y=0 \end{equation*} using the Frobenius method Homework Equations Assume a solution of the form \begin{equation*} y=\sum_{n=0}^{\infty}{a_nx^{n+s}} \end{equation*} then \begin{equation*}...

Homework Statement Determine the components of the forces acting on each member of the pin-connected frame shown. (the frame shown is drawn as a free-body diagram in the image provided below (the top-most portion) and is correct) Homework Equations Equilibrium equations: ∑M=0 ∑Fx=0 ∑Fy=0 The...

Use the method of undetermined coefficients to find a general solution of the ODE: $y''+3y'+2y=2x^{2}+4x+5$$r^{2}+3r+2=0$ $r=-2$ and $r=-1$ $y_{h}=c_{1}e^{-2x}+c_{2}e^{-x}$ I'm not sure how to get $y_{p}$ here So here's what I've done so far. I have my final exam tomorrow and I have a few...

Homework Statement I am trying to solve the following equation using the method of characteristics: ∂u/∂x + (xy)(∂u/∂y) + 2x2zLog[y](∂u/∂z) = 0 I'm really just trying to follow along the solution provided here: http://www.ucl.ac.uk/~ucahhwi/LTCC/sectionA-firstorder.pdf on page 9. The...

I studied this from Griffith Chapter 2, with the algebraic (raising and lowering operator) method, we reached the ground state by setting a_Ψ0 = 0 , then we got what the ground state is, and then plugged it in the Schrodinger equation to know the energy, and it turned out to be 0.5 ħω. My...

Homework Statement I have an object of a known mass, and known dimension along one axis (length). Mass: 10 kg Length: 2 meters I wish to calculate what the mass of an object that is similarly constituted and shaped will be if it has a greatly expanded length of: 1,000 meters. I am seeking to...

Homework Statement Find the extremizing (maximum) value of the function f(x) = sin x / x using Newton's 1D method. Homework Equations [/B]The Attempt at a Solution I know the maximum point in this equation is (0, 1). When I differentiated the equation twice and used the formula above, I...

Homework Statement A motorist drives along a straight road at a constant speed of 14.4m/s. Just as she passes a parked motorcycle police officer, the officer starts to accelerate at 1.8m/s^2 to overtake her. Assuming the officer maintains this acceleration, determine the time it takes the...

Is there any method to define weather I have to calculate for determine buckling of column lead to fail or not. Is there is any rule of thumb or formula that show it is required to check for buckling or not (like very short column)

If I have the following relations: X = sqrt(1-V^2)*cos(U) Y = sqrt(1-V^2)*sin(U) Z = V where (-pi < U < pi) and (-1 < V < 1) are independent random variables, both with uniform distributions. How do I use the CDF method to find X_pdf(x)? X_pdf(x) = X_cdf'(x) = ( P( X < x ) )' = ( P(...

Hello, a dubt arose while doing some exercise. If I have a charge q at a distance d from the above-mentioned plane, i can find the solution to the laplace equations (thanks to the uniqueness theorems) finding a collection of image charges that satisfies the boundary conditions. These conditions...

Homework Statement In the attachment. Homework Equations Chart of pressure loss due to friction for steel ducts : http://postimg.org/image/4iml9x761/ The Attempt at a Solution I don't understand the deltaP/L column of the results table. Where did the values come from? Shouldn't they all be...

I am trying to solve the differential equation ##\frac{d^{2}y}{dr^2}+(\frac{1}{r}+1)y=0## with the boundary conditions ##y(r) \rightarrow r \frac{dy}{dr}(0)## as ##r \rightarrow 0## and ##y(r) \rightarrow \sin(kr+\delta)## as ##r \rightarrow \infty##. I know that the shooting method is the...