Systems Definition and 1000 Threads

Homework Statement I have a trouble understanding what would be the output when for example we say let's input the signal x(k*n) or x(n-n0) to the system... this has given me problems when having to solve systems for which I have to check the property of time invariance suppose we have a...

I was just wondering about chassis ground in the context of a cars electrical system. If the return path back to the battery is through the metal chassis of the car, then what stops you from receiving a shock when you touch the car chassis ? Thanks.

Hi everyone, I am working through Ballentine's Quantum Mechanics books, and I am stuck... I would be appreciative if someone could walk me through this section with some help. Here is my first confusion. In this case then |a_{m'}b_{n'}\rangle\langle a_{m'}b_{n'}| do not form a complete...

In Fredrik's recent thread: https://www.physicsforums.com/showthread.php?t=506326 some questions arose about this paper: J. B. Hartle, "Quantum Mechanics of Individual Systems", Am. J. Phys., vol 36, no 8, (1968), pp704-712. [For other readers, you'll need to have read or be able to...

why there are so many number systems when we can only use anyone of them ? What's the need of octal and hexadecimal ?

Homework Statement Determine if the system y(t) = sin(x(t)) is time invariant, linear, causal, and/or memoryless. Homework Equations None. The Attempt at a Solution The system is time invariant and is non-linear, but I don't understand why it is causal and has memory.

Hi guys, Need a little help with an example my tutor and I are trying to work through. We're converting a dynamics system from a state space representation to a transfer function. This is where we are at so far... [s^2 + (C/Mb)S + (K1/Mb), -((C)S + K1)/Mb; -((C)S + K1)/Mw, S^2 +...

Hi guys/gals, First post here - in need of some desperate last minute help. Today is my last day to study and I will have my final exam tommorow. I've been doing past papers all day, and there a few questions I have no idea/never seen before in my course material. Part (c) I have no idea what...

Anyone knows any good online lectures on Signals & Systems theory?

Is it a linear system? Casual system? Please explain why and how.

1. x' + y' - x = -2t x' + y' - 3x -y = t^2 2. x' = Dx, y' = Dy 3. I eliminated x to get y alone by multiplying the first row by (D-3) and the second row by (D-1) (D-1)(D-3)x + (D-3)Dy = -2t(D-3) (D-1)(D-3)x + (D-1)(D-1) = t^2(D-1) then subtracted to get: (D+1)y =...

Hi all. Woohoo, I'm in diff eq now. Gosh, I've been on this board since Calculus I think. Sorry I usually only come around when I have a question. :\ Sooooo, Thursday my professor did an example of solving a system of linear differential equations with using the linear operator D...

can anyone give me an example of isolated closed system?,bcoz for me there is nothing called closed system,all we can make out is to reduce the temperature of a system to such a critical point that there's hardly any interaction/exchange of energy b/w system and enviroment

Hi folks. This is something I've been wondering about for a while now. Is there a reason why taking the minimum norm solution is the standard thing to do for an underdetermined system, or is it just an arbitrary tie-breaking rule?

hey... This semester we were taught basic operating system functionality...like paging,segmentation,virtual memory,demand paging,disk allocation,memory allocation,disk scheduling,cpu scheduling,etc...form Galvin operating systems book...now i want to learn more about operating systems...such as...

in a spring mass damper system subjected to a periodic force. the response of the system only depends on the force and the restoring forces caused due to the spring is ignored because the damper is assumed to have taken care of it. now it's here that my confusion originates. in a damped free...

I have two systems of linear differential equations: \frac{dx}{dt}=Ax, \frac{dy}{dt}=By x,y are vectors of length n and A,B are nxn matrices. I have a third system defined by: \frac{dz}{dt}=-ABz Is there anything we can say about what the third system represents in terms of the first two? If...

hello, If I have two LTI system in G1(s) and G2(s) and I know that for a certain fraction of the time period G1 is active and for the reminaing fraction G2 is active, then is there any method to get the equivalent transfer function ? Umat.

I posted this in "Materials & Chemical Engineering", but it seems a little more active here. I'm confused with trying to find the slip systems of a simple cubic. I understand the slip plane would be along the plane with the highest atomic density (a close packed plane). But I don't quite get...

Hello, I know that blackbody radiation was one phenomenon whose study contributed to the conceptual development of QM early on. My first question is, what other such systems were considered? I want to know this because I'm closely following the actual order of development of QM concepts, the...

I have encountered different naming systems in textbooks. Ignoring cis/trans, for example, some textbooks would give the name 2-butene, while others give but-2-ene. Are they both acceptable? The newer textbook uses the second type of naming, while the older textbook uses the first...

Those who are against superluminal communication often choose to look at a single set of 'entangled' particles as an example of communication between A(lice) and B(ob). For example, Patrick Van Esch: 'EPR, density matrices, and FTL signaling' that sees the two particles as ‘clearly defined...

Hi, {First off I should share my ultimate goal, which is to have a position function of time of several bodies, let's say in a solar system, so that the position of each body and the acceleration due to gravity on all the other bodies in the system are given at any time t. Although Kepler's...

What kind of systems do ODEs describe? What kind of systems do PDEs describe?

What are the basic elements in embedded systems? Can I use any microcontrollers, DSPs, and microprocessors in one systems. If yes, how is memory element linked with microcontrollers, DSPs, and microprocessors? On whose memory elements, codes are written? Which language is preferred for the codes?

I'm still puzzled by Loschmidt's paradox. In quantum mechanics, an isolated system has a unitarian time-evolution which implies that the (von-Neumann-) entropy remains constant at all times. (Contrary to the entropy-increase due to mixing in isolated classical systems for example) So whenever...

Hello all, I was wondering what is the Kronecker index in relation to dynamical systems. For instance a sample question would be find the Kronecker indices ind(0,x-F(x)) and ind(inf,x-F(x)) for the dynamical system {(dx/dt)=g(x,y),(dy/dt)=h(x,y)}. Thanks in advance.

Homework Statement I've attached the problem as it is easier to understand/view the circuit outline this way. Homework Equations If/3 = Ea/Ztotal Vag+=(If/3)*Ztotal(positive) +1 Vag-=(If/3)*Ztotal(negative) Vag0-(If/3)*Ztotal(zero) The Attempt at a Solution I know how to...

Homework Statement For the system u' = v, v' = −u with initial conditions u(0) = 1 and v(0) = 0, find an approximate solution by performing 4 steps of Picard iteration. Compare the results with the actual solution.Homework Equations In general: y'= f(x,y), y(x0)= y0 y(x) = y(x0) + \int...

Homework Statement So, I have found a general solution to a system of linear first order ODE's and this is what I got: X = c1v1e^(-1+2i)t + c2v2e^(-1-2i)t where v1 = [-1+2i, 5], v2=[-1-2i,5]. The question is, how do I now change this solution into its real equivalent? i.e. I don't want any...

I'm curious as to whether or not there is a method for solving higher-order systems of equations, for instance a system of a quadratic and two cubics in three variables, etc. I'm doing some independent research on the topic and would like to know if any methods currently exist to solve such a...

I am not an ME but I have a problem I am working on. I am looking for a mechanical system that would convert a short distance of heavy downward preassure into a strong amount of rotational torque on a wheel. For instance, 150lbs downward preasure over 2" distance converting to 50+ ftlbs...

Good day everyone. Could someone please explain what is meant by a linear time invariant(LTI) system? From what I have read on linear and time invariant systems separately. I would assume that a LTI system is one that obeys the principles of superposition and a shift in input causes a...

Homework Statement An ant walks from the inside to the outside of a rotating turntable. Write down it's velocity vector. Use polar the cartesian coordinates. Homework Equations I have already derived the velocity vector in polar coordinates which is: \hat{v} = \dot{r}\hat{r} +...

So I have a control systems mid-semester exam coming up and the lecturer has posted up a formula sheet for us. However it is different to past years exams and has a geometry section with the following equations: e^(±jθ)=cos(θ)±jsin(θ) cos(θ)=(e^jθ+e^-jθ)/2 sin(θ)=(e^jθ-e^-jθ)/2j Now I've...

one must create 250ml of a 17% salt solution. You have three stock solutions. One liter container of a 5% salt, a 500ml of a 28% salt solution and a 400ml of 40% salt solution. Calculate the cheapest method of preparing the 17% salt sol. if the 5% salt solution costs $28 per liter, the 28%...

Hello, I am trying to understand this partially rotated coordinate systems. I do not understand how does x'=xcos(theta)+ysin(theta) and y'=ycos(theta)-xsin(theta) I am probably stuck at silly answer but i need this to understand deriving of formulas for special relativity. Thanks

Hi, I am trying to simulate a freely jointed chain polymer to do that I want to put several rods (length a) on top of each other but with different angles. My problem is like this I have a vector(1) and at the end of this vector(1) I put another vector(2), the z-axis of this vector(2)'s...

Are all linear differential equations considered linear systems? Does the "linear" in both terms reference to the same characteristics? http://en.wikipedia.org/wiki/Linear_system http://en.wikipedia.org/wiki/Linear_differential_equation

The original form: http://img190.imageshack.us/i/79624585.png/ http://img685.imageshack.us/i/70092098.png/ I have manged to get to (D + 1)x + (D2 +D +1)z = 0 but after that I am kind of lost.

***Ugh, I'm so sorry. I think I put this in the wrong thread. It probably should be in Calculus and Beyond... I tried to delete it but didn't see that option.So my professor gave us this problem to work on but no one could figure it out. I don't know where to even start and there's nothing at...

Homework Statement I don't have a homework question. I have more of a general question. Let's say we have a solution... x=C1*[a1 a2]^{T}*e^{lamda1*t} + C2*[b1 b2]^{T}*e^{lamda2*t} As t approaches infinity how do you determine what the solution does? Homework Equations...

For a system of more than 2 particles each interacting with each other under a potential (conservative force), does the dynamics of anyone particle exhibit a conserved (energy) quantity --- in other words, is it possible to write down a conserved Hamiltonian for each particle? The reason I ask...

Homework Statement solve the 2 systems x1 + 2x2 - 2x3 =1 x1 + 2x2 - 2x3 = 9 2x1 + 5x2 +x3 = 9 2x1 + 5x2 +x3 = 9 x1 + 3x2 + 4x3 = 9 x1 + 3x2 + 4x3 = -2 the question gives this explanation by doing elimination on a 3x5 augmented matrix and the performing two back...

Hi All, when a power system is in peak demand how come the generators that create the power experience a speed droop and hence a drop in frequency? Can somebody please explain this to me in basic terms... I thank you in advance:confused:

I'd like to write (so not calculate, just "publish") some notes using mathematica. My very big problem in fact is the text-mode... How could I write a system of equations in mathematica, so that it appears "beauty", divided into multiple lines? I don't want something like this: f =...

Homework Statement What is that oscillatory component? And is my answer for the following correct? x(t) = u(t) H(s) = \frac{R}{R + sL} y(t) will contain oscillatory component if R > \frac{1}{L} True or False? Homework Equations Basic Laplace Transform: u(t) \longrightarrow...

Homework Statement 3. Generator G in the above system is a steam turbine driven, 4-pole round rotor synchronous generator and has the following data: Rated output 250 MVA Rated Voltage 13.8 kV Rated frequency 60 Hz Rated power factor 0.85 lag Maximum reactive power 140 MVAr...

Hi there, Physics lovers. I'm studying "The Classical Theory of Fields" from the "Course of Theoretical Physics" book series by Lev D. Landau, and I'm stuck with simultaneity in General Relativity. In page 251 of the Fourth "revised" english edition, by Butterworth Heinemann, There begins the...

Suppose that the solution set to a linear system Ax = b is a plane in R^n with vector equation x = p + su + tv , s, t ∈ R . Prove that p is a solution to the nonhomogeneous system Ax = b , and that u and v are both solutions to the homogeneous system Ax = 0 . (Hint Try choices of s and t)...