What is Systems: Definition and 1000 Discussions

A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and expressed in its functioning. Systems are the subjects of study of systems theory.

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  1. N

    Do these 3 systems of equations all all define the same curve?

    Homework Statement Consider three systems of equations: x^2 + y^2 + z^2 = 1 y^2 + z^2 = 1 x^2 + y^2 + z^2 = 1 x = 0 y^2 + z^2 = 1 x = 0 Which of these define the same curve and which define different ones? Homework Equations x^2 + y^2 + z^2 = R^2 is a sphere x,y, or z =...
  2. L

    Conservation of linear momentum applied to rotating systems? (with picture)

    Homework Statement I've encountered problems like this: A bullet with velocity v strikes a stick (intially at rest) at a distance d from the center of mass, then the bullet sticks to it, and the bullet-stick system rotates about the center of mass. But they ask me to find weird things like the...
  3. C

    How do you find initial values for linear discrete time systems?

    Can someone the following steps of this solution for me? http://imageshack.us/photo/my-images/828/80685231.jpg/ Mainly how they got their initial conditions? The 7.30 equation is just h[n-m] = bm which doesn't help me much. For our problem, I know that n=3 and m =1 since the LHS...
  4. P

    Laplace Transform of Systems of ODEs with variable coefficients

    Homework Statement Say you have: EQ1: y1''*t+y1'*t+y2=0 and EQ2: y2''*t+y2'*t+y1=0 y1(0)=0,y1'(0)=0,y2(0)=0,y2'(0)=0 Homework Equations The Attempt at a Solution I can get it so far, but having both y1 and y2 really gives me fits: Eq1: Y1(-2s-1)+dY1/ds(-s2-s)=-Y2...
  5. D

    Books on orbital transfers, satellite control theory, dynamical systems etc

    Hey folks wondering if anyone knows some good books on the following subjects... Orbital transfers, specifically to Lagrange points with information on stable/unstable manifolds. Control theory of satellites, new to control theory so perhaps I should be looking at a general control theory...
  6. D

    MATLAB Control Systems RLC Circuit Queries

    Hi there, we recently completed a laboratory session on MATLAB relating to an RLC Circuit and arrive at a code and relevant inputs and got our graphs as shown below. I was just wondering if anyone know if these are correct and make any sense? Or any other comments appreciated. We also have...
  7. pairofstrings

    Linear/Nonlinear, time-variant/invariant systems

    Hi guys. I am super excited to know answers of the questions that I am going to write below and want you to give me only the gist or a superficial information on the concepts and hopefully I will find the rest of the matter by-myself. Question 1: How do we solve Linear Time-variant systems...
  8. S

    An introduction to basic electronics and electric systems

    Hey all, was wondering if someone knows of a book (if it's on safari books online, even better!), website or other source that teaches me -- a software guy -- the basics of electronics. Basically I want to know about voltages, generators, capacitors and everything in-between. Wanna have my...
  9. G

    Shallow wave equations (First order quasilinear systems)

    Homework Statement I am trying to show the shallow wave equations (Pg 35 Ockendon). For a shallow channel of water, with one free surface h(x,t) that runs parallel to the x-axis, the fluid has a constant density and the pressure is nearly hydrostatic and equal to P(x,t)=ρg(h-y) Homework...
  10. A

    Nonlinear systems of differential equations

    The complete question I've been given: The Rossler equations are formally defined as dx/dt=−y−z dy/dt=x+ay dz/dt=b+z(x−c). Let us suppose that a=0.2, b=0.2, c=5.7, x(0)=y(0)=z(0)=0, t∈[0,400]. Let v1(t) be the solution to the given initial value problem, and let v2(t) be the solution of the...
  11. A

    Nonlinear systems of differential equations

    I think I posted in the wrong section and will repost in the textbook/coursework section but don't know how to delete this. Although if you want to answer feel free. The complete question I've been given: The Rossler equations are formally defined as dx/dt=−y−z dy/dt=x+ay dz/dt=b+z(x−c). Let us...
  12. K

    Self-Organizing systems discussion 2:

    Hello, I was reading into self-organizing systems and I decided to post on a few curiosities that i stumbled over because members here know more about this topic than I do. So if any of you will, give me some insights. [I am an undergraduate math student] I know a lot of findings within...
  13. K

    Self-Organizing systems discussion:

    Hello, I was reading into self-organizing systems and I decided to post on a curiosity that i stumbled over because members here know more about this topic than I do. So if any of you will, give me some insights. [I am an undergraduate math student] I read that studies suggest that through...
  14. C

    Systems of First Order Linear Equations

    Homework Statement Systems of first order equations can sometimes be transformed into a single equation of higher order. Consider the system (1) x1' = -2x1 + x2 (2) x2' = x1 - 2x2 Solve the first equation for x2 and substitute into the second equation, thereby obtaining a second order...
  15. B

    Systems of first order linear equations involving wronskian and matrices

    Homework Statement If y3(0) = 2y2(0) - y1(0), what is W(3)? Homework Equations \frac{d}{dt} y(t) = A(t) y(t), A(t) = [1 et e-t] [e-t 0 et] [2 sin(t) -1] The Attempt at a Solution I...
  16. P

    Dynamics of rotating systems

    Homework Statement A shaft 2 m long rotates at 1500 revs min–1 between bearings as shown in FIGURE 2. The bearings experience forces of 5 kN and 3 kN acting in the same plane as shown. A single mass is to be used to balance the shaft, so that the reactions are zero. The mass is to be...
  17. D

    Questions for Systems Engineers

    What degree program(s) did you pursue and where (U.S.)? What did you think of any coursework/program specific to Systems Engineering, especially in relation to previous degree programs? What sort of S.E. job prospects did you pursue/what was available (ex., internship that turned into a job...
  18. S

    Difficulty - Signals and Systems

    Hi In my notes I came across the following sentences:- Any signal consisting of the system's characteristic mode is sustained by the system on its own. The system offers no obstacle to this signal. Not getting what it means. Please, a little help needed. :-) Thanks salil
  19. L

    Convert DC to AC for Photo Voltaic Systems

    Hi there I have an Photo Voltaic system size 141 kW DC. It gives me an about 13 000 kW/hr a month.(I'm in Hawaii) We planning to install a new system, size ≈800 kW DC. How can i calculate how much of kW/hr AC i will get out of new system? Is there is any special formula to covert DC to AC...
  20. S

    Thrust to Power Ratios for Modern Propulsion Systems

    Does anybody know some ballpark figures for thrust to power, Newtons per watt, ratios for modern propulsion systems, mechanical drive train ie cars trucks, propeller driven craft, boats planes, and rockets. I've found one reference that states the F/P ratio for a DC-9 jet engine is 0.016 N /...
  21. L

    Feedback Control Systems as an Elective

    Hey everyone, I am an undergraduate mechanical engineering major considering a EE feedback controls course as an upper division elective. I have taken ME Control Systems and am also the Lab Instructor for it this semester. I am familiar with signals, filters, sensors, controllers etc. My...
  22. E

    Coordinate systems - finding optimal? simple conceptual question

    today in my physics course we were using jacobians to transform coordinate systems. This made me wonder if there was a way of deriving an optimal coordinate system to use for a given problem. -optimal meaning most simplified equation of a surface or bounds of a constraint (ex. cylindrical...
  23. S

    Systems of equations using partial derivatives

    Homework Statement Consider the system of equations x^2y+za+b^2=1 y^3z+x-ab=0 xb+ya+xyz=-1 1. Can the system be solved for x, y, z as functions of a and b near the point (x, y, z, a, b)=(-1, 1, 1, 0, 0)? 2. Find \frac{\partial x}{\partial a} where x=x(a, b) The Attempt at a...
  24. W

    Quantum systems without a classical limit

    in the literature, people are talking about 'quantum systems without a classical limit' could anyone give me an example?
  25. A

    Complex systems - how to start

    Hello everyone, I'm now 3rd (of 4) year on theoretical physics studies. Recently I become very intersted in complex systems and complex networks. Can anyone give me some hint how to start learning this, some books, online courses etc.? Regards!
  26. X

    Control Systems Question. Need to convert a plant from G(s) to G(z) (discrete).

    Homework Statement The system is given by: G(s) = 1/((s+0.1)(s+3)) I need to convert it to G(z), it's discrete form. The sample time T is 0.1 seconds. Homework Equations To convert it they give G(z) = (1-z^(-1))*Z-transform[G(s)/s] The Attempt at a Solution Obviously I...
  27. B

    Signals and Systems: Deriving length of discrete convolution signal

    Homework Statement If a signal f1[n] begins in a moment N1 and ends in moment N2, and signal f2[n] begins in the moment M1, and ends in the moment M2, derive the formula which states in which moment begins and ends the signal f1[n]*f2[n] Homework Equations The Attempt at a Solution I...
  28. S

    Naming systems physics vs biology

    (I think I could equally have posted this in the biology section!). I know nothing about formal structure of biology..and hope that I will be enlightened. My question is to do with naming systems in physics vs naming systems in biology.. In physics nearly all units that you care to...
  29. mnb96

    Curvilinear coordinate systems and periodic coordinates

    curvilinear coordinate systems and "periodic" coordinates Hello, we can consider a generic system of curvilinear coordinates in the 2d plane: \rho = \rho(x,y) \tau = \tau(x,y) Sometimes, it can happen that one of the coordinates, say \tau, represents an angle, and so it is "periodic"...
  30. 4

    Exploring Double Slit Experiment with Non-Light Systems

    can the double slit experiment be performed with systems other than light?
  31. A

    How to calculate entropy of mixing in 2-d systems

    Hello physics forums, I am writing a paper and I am wondering how to calculate the entropy of mixing in a two dimensional system. I am sure that entropy increases with mixing in a two dimensional system, but I do not know what equation to use. Would I just use the same equation as for 3-d...
  32. A

    Three magnetic systems in thermal contact

    Homework Statement "Consider three magnetic systems in thermal contact, each composed of N1, N2, N3 spins, +m or -m. Starting from s1 = s'1 + δ1 etc. calculate the average square deviation <si2 of each system. Homework Equations s'1 is the most probable configuration for s1. N1+N2+N3 =...
  33. X

    Shwoing the sensitivity of many body systems oi small perturbations

    Homework Statement Imagine we are observing the motion of frictionless, elastically colliding billiard balls. Using sensible assumptions about the size of things, show that, if someone enters the room, small deflections of the balls due this visitor's gravitational pull will completely...
  34. M

    General rule of resolution of optical systems

    According to Faynman Lectures on physics in the chapter of geometrical vol1 ch27, the general rule for the resolution on any optical instrument is this: Two different point sources can be resolved only if one source is focused at such a point that the times for...
  35. pairofstrings

    Become an Embedded Systems Engineer - Tips & Books for Success

    Please tell me how to become a successful embedded systems engineer. What books should I study...? I have a Bachelors degree in Electronics and communication. I have seen many job posts and requirements in it are huge. How can I achieve all those skills? Help!
  36. J

    How is center of mass in a complex systems?

    Now i am suddenly confused with the concept of the center of mass. As we know , nucleus are a system of many-body,composed of nucleons. And their interactions are very complex between nucleons. I want to know, If we can observe a nuclei such as Ne20, how is the motivation of its center of mass?
  37. A

    Systems of Linear Equations

    http://www.scribd.com/doc/66759813/mat223tut1" Question 2 and 3 Homework Statement For what values of c does the system have no solutions? I figured out the other ones, for c=0 we can assign a parameter to x1 and it will then have infinite solutions. For c=1 the system will have a unique...
  38. C

    Solving Systems of Congruences when mods not pairwise relatively prime

    Hi folks, The CRT says there's a unique solution to the system of congruences x = a (mod m) x = b (mod n) x = c (mod p) in (mod mnp) when m, n, p are pairwise relatively prime. But what if m, n, p are NOT pairwise relatively prime. Is there a systematic way to solve...
  39. B

    Oscillating mechanical systems. find maximum velocity and acceleration ?

    Oscillating mechanical systems. find maximum velocity and acceleration !? A mass of 0.3 kg is suspended from a spring of stiffness 200 N m–1. If the mass is displaced by 10 mm from its equilibrium position and released, for the resulting vibration A) Calculate maximum velocity B) Calculate...
  40. T

    Discrete Math: Symmetric Closure & Numerical Analysis

    Discrete Mathematics -- Symmetric Closure Math help in Numerical Analysis, Systems of I can't seem to find the way to approach this problem. Because it has symbols I don't know how to type here, I have attached an image here instead. Please help me if you can. Any input would be greatly...
  41. P

    Find 4th Edition of B P Lathi's Digital, Analog Communication Systems

    hi everybody..i do need the 4TH EDITION of b p lathi"digital,analog communication systems"..can anyone help me?
  42. B

    What Do Vertical Lines in Signal Graphs Represent?

    So I am 2nd year now and we started this new course Theory of Signals. Already I bumped into a wall when it came to understand basic stuff. Here is what I mean [PLAIN]http://pokit.org/get/0864633c869b647116b980428a07d4f1.jpg Here we have 4 functions, each representing one type of...
  43. L

    Combining Coordinate Systems?

    While not paying attention in class my friend made a joke that a cube squared was in six dimensions, or something like that. Terrible joke, but now I'm trying to figure out if it is valid to arithmatically combine the basis vectors for two or more coordinate systems to get a new one.
  44. N

    Boltzmann factor (canonical) only for extensive systems?

    With an extensive system, I mean a system where energy is an extensive variable. But no need to state it so generally, since I have a specific system in mind which will make sure we don't get into a battle of semantics: if you double the size of a gravitational system, the energy is not...
  45. H

    Aqueous systems questions

    I had these two questions in a test and I was completely stumped. 1. Make a 1-2L buffer solution containing methanoic acid and methanoate ions and with a pH of 3.74 using 1.07molL-1 HCOOH, solid HCOONa, 1.04molL-1 HCl, 1.16molL-1 NaOH(not all together). pKa(HCOOH)=3.74 M(HCOONa)=68gmol-1...
  46. S

    Solving Binary Star Systems: Doppler & Kepler's 3rd Law

    Application of the Doppler effect and Kepler's 3rd law Homework Statement (*This isn't the exact wording from a textbook, just as I had copied it down) An eclipsing binary star system containing stars A and B in concentric orbits (about their common centre of mass) has it's maximum red- and...
  47. J

    Is a System Causal if the Output Anticipates the Input?

    Hey guys, having a little trouble understanding whether or not a system is causal or not. I d'nt think this classifies as homework; at least I hope not. Basically I'm confused as to how you would go about determining whether or not a system is causal. For example, say any function x[n] =...
  48. pairofstrings

    Is it OKAY to choose Embedded systems?

    I know the recession is upon us therefore, I want to know if recession can affect any fresher in this times who opt for career in Embedded systems. How is the job market in USA or around the globe for Embedded systems? Are any companies hiring new people in Embedded systems?
  49. W

    Exploring "True" vs. Measured Degeneracy in Physical Systems

    Firstly hello, this is the first time I have posted here (although I have used the site to find info in the past). My query is best illustrated, I think, with an example. Suppose we have some physical system with corresponding state vector \left| \psi \right> = a \left| 0 \right> + b \left|...
  50. T

    Linear equation, span, vectors, linear systems of equations

    show that S and T have the same span in R^3 by showing that the vectors in S are in the span of T and vise versa. S= {(1,0,0), (0,1,0)} T= {(1,2,0), (2,1,0)}im a little confused on how to start off on this problem.. help?!
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