Systems Definition and 1000 Threads

Homework Statement Hi, I'm doing nodal analysis and I end up with 3-5 equations that need solving simultaneously. I have been sticking them in mathematica and letting it do its thing but I need to be able to do it on my 89 too. The trouble is that there not in a matrix friendly form - - -...

So I am reading a text written by my Thermodinamics professor and I find something that I still can't accept. "(Sistema fechado) É aquele que não troca massa. (...) Um sistema fechado é dito isolado quando não troca energia. Entretanto, essa definição de sistema não é consistente com a teoria...

Help! I'm a third-year chick in engineering, stuck on a block diagram reduction problem for my control systems engineering course. Please email me and I'll send you a screenshot of the problem! kati@sidwall.com Thanks a mill. K xo

Hi everyone, Given two different reference frames in a vector space; say left and right. v is a vector defined in the left frame and u is a vector defined in the right frame. What is the nature of a matrix A that can satisfy the equality u= A.v? Thank you

Hi guys, I'm a pure math master degree. Interested in studying dynamic systems, I want to learn more about this subject without any academic course.(just self study) How can I start it? Which books , articles and subjects?

Dear Colleagues, I would like to submit to your court the article in which we attempt a physical analysis of living matter. Biology is a very difficult field for physics as a result errors are very likely. We would appreciate guidance on possible errors. Prokhorenko DV and Matveev VV. The...

Matrix Systems of ODEs -- Mathematica I'm trying to solve the classic "systemm of linear ODEs" of the form: Y(t)' = X*Y(t) Its homogenous, so it wouldn't hurt to rewrite it as Y(t)' - X*Y(t) = 0 (if that helps?) so here is my attempt at the solution solExp == NDSolve[Y'[t] ==...

Hi. Anyway, learning this sort of makes me feel like I've chosen the wrong school for myself, but I'd like to try and see if I can understand this nevertheless. See, I'm supposed to learn various numerical methods for solving systems of linear equations, like the Jacobi or the Gauss-Seidel...

I'm just wondering if the tension between the masses, that is the tension from the string, is different between each mass in the following situations. Like is the T between m1 and m2 different from the T between m2 and m3? Is it for both situations or is the T the same all around in one of the...

Homework Statement given this discrete time signal x[n] = u[n] - u[n-6] find for which n the even part of x is 0The Attempt at a Solution the even part is x' = 1/2(x[n] + x[-n]) = 1/2(u[n] - u[n-6] + u[-n] - u[6-n]) now i find that u[n] + u[-n] is 2 for n = 0 and 1 for n != 0 u[n-6] +...

Homework Statement In the figure here three ballot boxes are connected by cords, one of which wraps over a pulley having negligible friction on its axle and negligible mass. The masses are m1 = 28 kg, m2 = 45 kg, and m3 = 12 kg. When the assembly is released from rest, (a) what is the...

Question : State which type of thermodynamic system (Isolated, Closed, Open) the following are... Include in your answer which type of system they are relative to short and long time periods. A list then followed. I'm unsure about only one. A thermal flask. I know in the long term a...

Hi everyone, I was looking for a std to calculate stability of truck mounted crane. Recently I found an australian std "australian code of practice for crane installation on truck" (I think it is a part of 1418 au std), and I found it simple and practical. But, when I tried to solve the example...

Currently working on a pet project, looking to build a model for accelerating a relatively large mass on a short straight track type system. Can't find much information about the way "Maglev" trains accomplish their propulsion or the way the electromagnet systems work to keep the train...

Homework Statement For any system of particles held together by mutual attraction U(potential) = -2 U(Kinetic) Suppose you add energy to such a system and wait for it to equilibrate, does the total kinetic energy increase or decrease? ExplainHomework Equations The Attempt at a Solution...

Homework Statement Find all Equilibrium points for the following systems. B. dx/dt = 5x - x^2 - 3xy dy/dt = 8y - 3xy - 3y^2 The Attempt at a Solution 0 = x(x + 3y - 5) 0 = y(y + x - 8/3) Equilibrium points: (0,0) but I can't find anymore? is (0,0) the only one?

Hello, first time posting. If this is in the wrong forum, please move it to the correct one. (its a cross mechanical/structural/civil/electrical engineering idea) I was thinking on the way home Power generation. In order to generate power, wave motion can be used (such as tidal/wave power...

Okay, so I understand that galaxies spin more like a frisbee than the solar system, and that there is evidence for a lot of non-light-emitting mass (such as gravitational lensing) but how would dark matter account for the difference in the spin of galaxies? Gravity still decreases inverse to the...

The usual eigenvalues of a LTV system does not say much about the stability but my intuition tells me there should be some kind of extension that applies to LTV systems as well. Like including some kind of inner derivative of the eigenvalues or something, I don't know... I guess in some way...

Hydraulic systems problem, need help urgently I need to get an idea of what kind of forces one can get with real world hydraulic systems. I need to be able to deliver a huge force very quickly. The magnitude of the force should be enough to accelerate a 50kg cylinder to 22m/s over a distance of...

Suppose you have a dissipative system where \dot{q}=p/m \dot{p}=-\gamma p -k\sin(q) So there isn't a Hamiltonian for this system and Louiville's theorem doesn't hold. But the equations of motion still give us a vector field on phase space and we can still take the Lie derivative of...

In making comparisons on efficiency in acquired ambient light for imaging devices, whether they be CCD and CMOS cameras or reflective displays, it seems the factoring is always based on Red, Green and Blue as if those are the only bands of visible light. For example, in acquiring\reflecting the...

Hi, I want to ask a quick question about the occupancy of energy levels in systems governed by different distributions. There exists a system of two particles, each of which may occupy one of two energy levels. Consider three cases: 1. Distinguishable, classical particles 2. Fermions...

Could anyone suggest me good books for mastering control systems?

Could anyone suggest me good books on power electronics,power systems and calculus?I belong to Electrical and electronics department.

1) Find an equation relating a, b, and c so that the linear system 2x+2y+3z = a 3x- y+5z = b x-3y+2z = c is consistent for any values of a, b, and c that satisfy that equation. what is the method to solve this problem? 2) In the following linear system, determine all values of a for...

Why are solar systems and galaxies flat? I find it peculiar that astronomical clusters (ie: solar systems and galaxies) are arranged in a flat plane. Can someone explain why? I understand that: any solar system originates from a random cloud of dust and gas. This cloud will feel its mutual...

Homework Statement Find the solution of the system x' = 3x + 4y; y' = -2x-3y satisfying x(0) = 2 and y(0) = -1 Thank you Homework Equations The Attempt at a Solution My method involves linear algebra: turn the pair of equations into a single first order vector differential equation of...

Homework Statement A unity feedback system of the form: X(s)-------->Gc(s)---------->G(s)------------>Y(s) | | | | ----<------------1---------<---- has a plant: G(s) =...

What is the difference? I used to assume First order was a Single DOF system and a Second order was a 2 DOF system. Can anyone give me some clarity. Thanks

Homework Statement http://img202.imageshack.us/img202/3496/71042279.jpg Homework Equations F = Fu The Attempt at a Solution Okay, so um I'm having trouble with this particular question. Normally if the wires were all straight, I'd have no problem solving this. But for this...

Homework Statement Please see attached problem Homework Equations The Attempt at a Solution Ok so I am just stuck on the bit that asks us to write down the appropriate form of the interaction hamiltonian H int for two oscillating particles connected by a weak spring. Is it 1/2...

Homework Statement Convert the differential equation for x, x''' + 2(x''2) = 0 Into a system of first order differential equations. Put the system in vector form Homework Equations The Attempt at a Solution I'm able to do this for simpler DE's but I can't seem to find an...

I know how they differ from one another, but what are they physically? Are humans closed systems, because we are able to exchange energy between us and our surroundings, but what I am trying to learn is the kinds of systems in chemical reactions: which elements react to form different systems...

Homework Statement Determine whether or not each of the following signals is periodic if signal is periodic determine the fundamental period (note that these are discrete not continuous signals) Show your solutions 1. x(n) = \cos^3(\frac{\pi(n)}{8}) 2. x(n) =...

Homework Statement Compute Y(t). Homework Equations Y(s)= (s(2s+11)+ω(8s+4ω^2))/((s^2+ω^2)(s+9)(s+2)) The Attempt at a Solution (s(2s+11)+ω(8s+4ω^2 ))/((s^2+ω^2)(s+9)(s+2))= A/(s^2+ω^2 )+B/(s+9)+C/(s+2) Every example I have looked at does not have the ω variable, but I...

Hi guys, i wanting to learn embedded systems and its programming through C language can you people suggest some good books on this subject.

I just want to ask a simple question: Is it true that Newtonian/Classical Mechanics does not hold true for all coordinate systems, while General Relativity does?

Homework Statement A uniform beam |AE| at 2m from A there's a 500N force at 60degrees to the negative x-axis direction. At 3.5m from A (1.5m from the 600N) There's a 200j N force and at 4.5m from A there's a -100i N force acting 0.5m above the beam. i)Determine the single force which is...

Homework Statement Consider the implicit (not actually sure wether that's the correct english word, my material is in Finnish and I'm Swedish-speaking :smile:) method xj+1=xj+h/2(f(tj,xj)+f(tj+h,xj+1)) a)Write an appropriate Runge-Kutta scheme b) What is the methods rank when we use the...

Hi friends, I'm new in this forum and very happy to be here. I need your guidance on what to do with my Signals and Systems course which I expect to turn into a failure. I'm studying Electronics Engineering and I think I'm going to fail Signals and Systems because I got 9 out of 100 on my first...

Hello! I`m looking for Lagrangian Systems with Lagrangian function containing higher derivatives in t. I would be really happy if someone can tell some higher order Lagrangians with physical relevance. Thanks, Viktor

I'm having trouble understanding what a deformable system is? Please give me a detailed example with your explanation. Thanks!

It surprises me how much mathematics is needed to solve the innocent-looking 2D Ising model, and the Heisenberg model is quite an exercise even in 1D. I begin to doubt whether solving these models is really worth the effort, given that these systems don't look very realistic, and computer...

From the lecture notes: h[n] = \frac{1}{2}(\delta[n] + delta[n-1]) via property: H(e^{j\Omega})=\sum_{-\infty}^{\infty}h[k]e^{-j\Omega k} becomes: H(e^{j\Omega})= \frac{1}{2}(1 + e^{-j\Omega}) than my lecture divided by e^{\frac{-j\Omega}{2}} resulting in: H(e^{j\Omega})=...

Homework Statement Input and system response is as follow: x[n] = r[n] - 2r[n - 1] + r[n - 2] h[n] = \delta[n - 2] The output is: y[n] = u[n - 3] Is that true? Homework Equations The Attempt at a Solution I draw the h[n] and x[n] and they looked as follows: As for...

1.Homework Statement We know the derivation of the method of variation of parameters for second order scalar differential. The task is to derive the method of variation of parameters for scalar equations using this approach: first convert the scalar equation into the first order system and...

Homework Statement The system with impulse response h(t) = a_{1}\delta(t-t_{1}) + a_{2}\delta(t-t_{2}). Is this system stable or not?Homework Equations The Attempt at a Solution I drew the h(t) response and I got something like that: but I don't really know how to prove it. There is no input...

http://www.edenpure.com/ Curious if these actually help people with heating costs. Looking for any testimonies from PF members, or close friends of PF members. While I understand the claims would vary from situation to situation (size of home, apartment vs. stick built house, w/ vs. w/o...

Hi, Can anyone explain what the steady state of a electric/electronic system is? as well as its significance and importance? is it the same as a dc steady state?