Constants Definition and 486 Threads

hi suppose i run Two notebook and in each of them i have matrix A and Constant B and a function C in each notebook these things have the same name. if in notebook 1 i assign B=10 then in notebook 2 B is 10 too , which is not my desire. how can i define these constants and matrices and...

Homework Statement Given the magnetic field B= α*x*y x^ + β*y^2 y^. What is the relationship between α and β. Find the current density J. Homework Equations I know that the relevant equations are Δ dot B = 0, Δ x B = μJ, Δ dot A = 0, Δ x A = B The Attempt at a Solution I know...

NONE OF IT MAKES ANY SENSE! For example: If we divide the molar coefficients all by 2, then we raise the original equilibrium constant by the same power (0.5). If we write the reaction in the reverse, then the new equilibrium constant is the multiplicative inverse of the original...

Hi, Let's say I have a 10 dimensional Lie algebra over some field of functions, something along the lines of at least twice differentiable with twice differentiable inverses. The structure constants have inputs from this field. Is it possible to build a metric from these structure...

The question I'm trying to solve is part (ii) of the attached file I've used partial derivatives to input back into the Black Scholes equations and after factorising it, I've got it down to: (a + 2bt + αt +r) * (S².c.e^(at+bt²) = 0 I'm now stuck on what to do next, as there would need to be...

Homework Statement So I need to prove that transversly isotropic materials have 5 independent elastic constants. I can prove that an orthotropic material has 9 independent elastic constants. I need to use the transformation matrix to show that some of the 9 mentioned components are equal for...

Homework Statement I have an integral that I'm trying to split into partial fractions, and I've gotten to an equation but I'm not sure how to solve this one. Homework Equations The Attempt at a Solution 93x+2 = Ax^2 + Bx + A - 4B I have no idea, because I usually don't have a...

Homework Statement Consider the differential equation -\frac{d^2u}{dx^2}=cos\pi x for 0<x<1 subject to the boundary condition u(0)=0, u(1)=0 Determine a three-parameter solution, with trigonometric functions the least-squares method Given: u=\phi_0 + c_1\phi_1 + c_2\phi_2 +...

I just got this question on a classical mechanics assignment... and unfortunately I know NOTHING about dielectric materials (never been introduced to me for some reason >.<). I don't even know why this is on my classical mechanics assignment but it is anyway. And btw there is a disclaimer on the...

I've been trying to compute the bending-torsion coupling constants for a wing, B1, B2 and B3. The expression for this is \begin{bmatrix} B_1 \\ B_2 \\ B_3 \end{bmatrix} = \iint (y^2 + z^2)\begin{bmatrix} y^2 + z^2 \\ z \\ y \end{bmatrix}dydyz where x is in along the wingspan direction, y...

Let a\vec{A}+ b\vec{B} + \vec{C} = 0, where \vec{A} = (75, -60), \vec{B} = (-16, 60), and \vec{C} = (84,16). I need to find the value of a and b. I really have no idea where to start with this problem any help would be great!

We know that in GR it is not possible for arbitrary spacetimes to define a conserved energy by using a 3-integral. There are some obstacles like the covariant conservation law DT = 0 (D = covariant derivative; T = energy-momentum-tensor) does not allow for the usual dV integration (like dj...

Homework Statement I have been given a 3X4 matrix and asked to find whether the plane equations which are it's constituents intersect at least at a single point. I end up with one variable equal to two different constants. Is this an example of inconsistency, and thus the planes to not...

From my understanding, the equation that models the transverse vibration of a beam is (Euler Bernoulli): u_{tt} = - \frac{EI}{A \rho} \cdot u_{xxxx} where E is Young's modulus, I is the 2nd moment of area, A is the cross-sectional area, and rho is the density of the beam. This equation...

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Hello, I am currently studying RL circuits and I know that when an inductor is attached to a resistor of large value, the time for the energy stored in the inductor to dissipate in the resistor is shorter and vice versa. This is proven mathematically by the time constant term Tau : L/R But...

How do you plot arbitrary constants in mathematica? for example r(psi)=a(1-eCos(psi)), where a and e are some constant. Thanks in advance for the help.

The general expression for calculating net potential energy in ion is: PE (r) = A r^m + B r^n where A & B are proportionality constants. What exactly are these constants?? Could anyone point me to correct resources?? I'm new at this forum and very interested in learning physics.?

Solve, floor(x/B)+1=L, for x, where B & L are constants & is a variable? Homework Statement I'm trying to solve this for x floor(x/B)+1=L where x is a variable B and L are just some constants Homework Equations The Attempt at a Solution I have no idea were to go after this floor(x/B)=L-1 I...

For a project, I'm trying to describe the interaction energy between two particles suspended in water which contains ions. I seem to have the double layer effect worked out pretty well, but I'm having trouble with the Van der Waals contribution, or more specifically, with the choice of Hamaker...

Homework Statement A 5.0kg mass is hanging from a spring scale and is slowly lowered onto a vertical spring. The scale reads in Newtons. a) what does the scale read when the mass is not in contact with the spring? b)the scale reads 20N when the lower spring is compressed by 2.0cm. show...

Homework Statement A mass of 40.0 grams is attached to a vertical spring with a spring constant k = 20.0 N/m and lowered slowly until the spring stops stretching. How much is the spring stretched? The Attempt at a Solution I assume I have to use F = -kx? But I don't know the force so...

Does the compressibility factor of a gas say anything about Van der Waals constants?

Does anyone know of any instance where the the time constants of two RC circuits in series is additive. It seems that when R1=R2 and tao1~tao2 this holds?

Homework Statement "Expressed in terms of the constants in this model, how high is the lowest point of the cable? (Assume the correct dimension to be in metres)"Homework Equations Equation for the shape of a hanging cable. [PLAIN]http://img59.imageshack.us/img59/8672/eqn6142.png edit: P, g...

Homework Statement A practical current source has a current of 22 A. Loading the source with 50 \Omega results in terminal voltage of 390.3 V. Obtain the source constants, I and R.Homework Equations V=I\times RThe Attempt at a Solution In my clumsy picture below, shouldn't I_{load} be replaced...

Homework Statement Part of a larger problem. I know that F_{1}^2+2F_{1}F_{2}-F_{2}^2=0 where F_{1} and F_{2} are x and y components of a force. Hence \frac{F_{1}}{F_{2}}=1\pm\sqrt{2} I can't see how that step is done. Homework Equations The Attempt at a Solution...

I can accept that spacetime has no substantial aspect to it because for General Covariance (Diffeomorphism Invariance) to be true, spacetime "points" can't be real or else General Covariance won't work. Now question. How does Inflaton Field and the Cosmological Constants for example interact...

Calculating distance using spring constant, mass and velocity? (Really basic stuff!) Hi I have a physics exam tomorrow, and I just realized we haven't covered either impulse or spring constants, and about 1 1/2 hours left to study. From a practice exam, please someone help me out? Homework...

Hey folks, i have a question about LSZ and how to take into account the renormalization constants of the theory in question. In the derivation, only the field strength renormalization enters as a factor of Z (or square root thereof) but some mates said that also the vertex renormalization...

Homework Statement http://img193.imageshack.us/img193/3696/aasdff.th.png Uploaded with ImageShack.us The Attempt at a Solution (a) No current, so no time constant since C = 0 for it stores no charge (b) Current immediately is driven through so \tau = (R_{1}+R_{2})C (c) I pulled the...

Hi, I have been deriving the renormalisation constants in QED as part of my project. I have been using Peskin and Schroeder. I am a bit confused with a couple of things and was wondering if anyone could please help! Firstly, why do we chose not to absorb the Z_3 constant in the electron...

Homework Statement Find constants a, b, and c such that the graph of f(x) = ax2 + bx + c has a relative maximum at (5 , 12) and crosses the the y - axis at (0 , 3). Homework Equations Not sure what to use The Attempt at a Solution -- i don't have one --

Homework Statement So I have attached the problem in image: Pr and A are just numbers (constants) that are given. I solved the equation by power series solution. However, I am just confused because it is a second order DE but I only have one arbitrary constant of integration ao. I am not...

Check this out, 1/(x2+a) where "a" is a constant When this function is integrated, if a is positive then we get something like arctan of something, if a is 0 we simply get -1/x, and if a is negative then we get something involving the natural logarithm, and yet there's something very similar...

Power delivered by Battery to Capacitor in "Time Constants" Homework Statement < Pic 1 > The Attempt at a Solution < Pic 2 > As you see, I'm getting answer as (ln 2)/2 but the answer is just (ln 2) Please tell me where I'm wrong.

Hello, I've been looking for a few rotational/vibrational diatomic molecular constants for N2 and O2. I've got a some good literature values for most constants I need involving the calculation in possible vibrational and rotational energy states. I'm looking for the centrifugal distortion...

Hi all, I remember in the Elegant Universe (the documentary), at some point the following lines were said: "So what exactly, in nature, sets the values of these 20 constants so precisely? Well the answer could be the extra dimensions in string theory. That is, the tiny, curled up...

[b]1. Make these three equations orthonormal to each other in the interval 1 less than or equal to x greater than or equal to 1 (this may be a typo as I think it should read 1 less than or equal to x less than or equal to one) by determining the appropriate values for the coefficients a b c d e...

Homework Statement A bubble of air, 0.010m^3 in volume , is formed at the bottom of a lake which is 30m deep and where the temoperature is 8 degrees c. The bubble risees to the surface, where the water temp is 26 deg c and where the pressure is atmospheric pressure. What is the volume of the...

Do we have at present any knowledge whether our natural constants (gravity constant, Planck's constant, ...) are rational or irrational numbers? Thanks, Trinitiet

Can someone please just explain to me how to do this? I feel helpless. A spring has a force of 500.0 N/m. Show that the potential energy stored in the spring is as follows: a.) 0.400 Joules when the spring is stretched 4.00cm from equilibrium. b.) 0.225 Joules when the spring is...

Hey, The decomposition of A is first order, and [A] is monitored. The following data are recorded: t / min 0 1 2 4 [A]/[M] 0.100 0.0905 0.0819 0.0670 Calculate k. Using [A] = [A]0e-kt, Calculating at t = 1 0.0905 = 0.1e-k(1) 0.905 = e-k -0.0998=-k k =...

On this page below, the person chooses the constants to be anything they want, but can you actually do that? Pauls Online Notes : Differential Equations - Reduction of Order

I have x(t) = C(sub1) sin(16t) + C(sub2) cos(16t) Given: initial position x(0) = 1/6 so: 1/6 = C(sub1) sin(0) + C(sub2) cos(0) 1/6 = C(sub2) but how do i find C(sub1)? I am not given initial velocity

Homework Statement Consider a 3-dimensional one-particle system whose potential energy in cylindrical polar coordinates \rho, \theta, z is of the form V(\rho, k\theta+z), where k is a constant. Homework Equations The Attempt at a Solution I already find a symmetric transformation: \rho...

I have been reading that observations of distant quasars over the past decade have been suggesting that there have been minuscule changes in our physical constants. An estimate was given about 1 part per 100000 every billion years. If such a change is indeed happening, then it is safe to assume...

I know how to measure Km, but I already know Kt from the datasheet and according to some motor calculation guide's I've found online, they say you can know one from the other by using the relationship: Kt (oz.-in) = 1.345 * Km (V/1000 rpm) I checked this on other motor's datasheets that give...

hi there I wnat to calculate the group constants for a FA(fuel assembly) using MCNP (similar to lattice calculations). How can I do it? Please lead me. Thanks alot!

Homework Statement Find y'' if y=1/3(1+cos^2(√x)) Homework Equations The Attempt at a Solution Now I believe I got the first derivative right since the teacher marked ir right, but my real question here is what do I do with the 1/3? Is it ok to throw away the constant when I...