Poles Definition and 225 Threads

Hi, Recently I came across an annular permanent magnet (round magnet with a hole in it) which had fallen and broken in half, effectively forming two horse-shoe magnets. I noticed that the two halves had similar poles: |---------- S S-------- | | |...

Hello all. I have two questions. 1] How do poles and zeros relate to bode plots? What happens at a pole or zero? 2] Can you come up with a rough sketch of a bode plot if you know the following (without having to use the transfer function)?: - Zeros - Poles...

Hello, I hope somebody can help me with this one. Homework Statement I want to find the integral of 1/x^N*exp(ix) from -inf to inf. Homework Equations It is very likely that this can somehow be solved by using Cauchy's integral formula. The Attempt at a Solution I tried to...

Consider 2 cases case 1: no of rotor poles = 2 no of stator poles =4 case 2: no of rotor poles = 4 no of stator poles =2 What will happen in case 1 & 2 ? Will Induction motor run?

I was wondering what voltage or current, if any, would be produced if the basic magnet through a copper coil experiment had the poles rotated 90 degress so north and south faced the top/bottom of the coil rather than the entry/exit points? The attached image has a basic illustration of this...

Hi all, I am studying QFT using John Preskill's notes. I have a question about the propagator and poles. On page 2.91, at the bottom, he said that there is a s-channel pole, which is the pole of the exact propagator. Then he claimed that by the argument about unitarity in page 2.70, the pole...

why poles of machine are always even?

Referring to following video, starting at 3 min. Earth's Magnetic Field deflat the Solar Storm. I would like to know more what is going on between the periods before Solar Storm hits Earth's Magnetic Field and after Solar Storm hits Earth's Magnetic Field? Does anyone know any...

Homework Statement Homework Equations Where are the north and south poles of this magnet? Where are the north and south poles of the wire's magnetic field? The Attempt at a Solution I used the Right hand rule to determine the magnetic field of the wire, but I got confused when trying to...

Homework Statement Find the order of the poles of f(z)=z/(e^z-1) Homework Equations The poles are at z=2 π i k k\inZ\0 (Because at z=0 f(z) has a removable singularity -set f(0)=1) The Attempt at a Solution I tried using the Taylor series of e^z - \sumz^n/n! But I just...

I know that \int_{- \infty}^{\infty} e^{-x^2}dx = \sqrt{\pi}. What if I tried evaluating this over the complex plane? If I created a contour that ran along the real axis, then circled around from positive to negative infinity this should not change things as along the curve at...

I was wondering what the difference in the magnetic poles north and south is and what makes them unique.

Hi, I'm new here, but it seems there are some pretty intellectual people running around. I was researching magnetorheological fluids, simply because I came across them and thought they were really interesting. I learned that when they are subjected to a magnetic field, the iron particles in...

Homework Statement A student finds an old magnet at the back of a drawer containing other magnets. He designs an experiment to find out if it is still magnetised. (i) He brings a plotting compass near to end A of the old magnet, as shown in the first part of the image. State the...

Is it possible for a magnet to have same poles? i saw a question in which the compass points the same way in both ends.

Please find the attached picture.. My understanding : Use right hand thumb rule to find the direction of magnetic flux lines when the direction of currents are known. When I have a 'cross', the lines will be in clockwise direction while I have a 'dot', the lines will be in anticlcokwise...

Hi! From "Le Bellac, Quantum and statistical field theory, 10.5.2-Massive vector field": "The longitudinal part of the propagator k_{\mu}D^{\mu\nu} has no pole at k^2=m^2, so the longitudinal part doesn't constitute a dynamical degree of freedom." I have two questions: 1) Why the propagator...

Can someone help me to expand the following gamma functions around the pole ε, at fisrt order in ε \Gamma[(1/2) \pm (ε/2)] where ε= d-4

I am supposed to discuss the benefits of having high number of magnetic poles in ac generators with constant frequency. From formula it is obvious that the higher number of poles the lower the speed of rotation. But is there anything else, or what is the benefit of lower speed? The only...

Hello, Generally and specially in AC motors, what is the effect of the no of poles of the rotor on the motor performance? if it's same or less or more than the no of poles of the stator? Thanks

Homework Statement evaluate the integral: I_1 =\int_0^\infty \frac{dx}{x^2 + 1} by integrating around a semicircle in the upper half of the complex plane. Homework Equations The Attempt at a Solution first i exchange the real vaiable x with a complex variable z & factorize...

Compute the residue of $\Gamma(z)$ at each of its poles. So the poles are at the negative integers and 0. I suspect there must be a formula than since this is an infinite set. $\Gamma(z) = \dfrac{e^{-\gamma z}}{z}\prod\limits_{n=1}^{\infty}\left(1+\dfrac{z}{n}\right)^{-1}e^{z/n}$ Should I...

Topic. If I have an iron shaped like a bar magnet placed flat on the floor, can the poles of the magnet be pointing anywhere else other than 90 degrees and 180 degrees?

$$ \int_0^{\infty}\frac{(\log x)^2}{1 + x^2}dx = \frac{\pi^3}{8} $$ I have no idea what to do with this integral. I can't see it is even and do 1/2 the integral from -infinity to infinity since log -x doesn't make sense.

Homework Statement \int_{|z-2i|=2} = \frac{dz}{z^2-9} 2. The attempt at a solution I know that the contour described by |z-2i|=2 is a circle with a center of (0,2) (on the complex plane) with a radius of 2. The singularities of the integral fall outside of the contour (z+3 and...

I am currently conducting a project where a yacht will be suspended in air by two straps which are connected together by two poles. The poles will be mounted on a barge and therefore I want to find how I can relate the angle of heel (\varphi) to the two angles. Although the yacht will remain...

Hi I'm working on a science experiment and I need two electromagnets to push away from each other, but the two small electromagnets I've made (using two bolts wrapped in magnet wire and a D battery) just attract each other no matter which ends I put together. Am I doing something wrong? Do I...

If f is meromorphic on U with only a finite number of poles, then f=\frac{g}{h} where g and h are analytic on U. We say f is meromorphic, then f is defined on U except at discrete set of points S which are poles. If z_0 is such a point, then there exist m in integers such that (z-z_0)^mf(z)...

This has been on my mind for quite a while. The LHC controls and accelerates particles with superconducting magnets, but then is the idea of magnetic domains in magnetic materials wrong as it paints the picture that electrons are causing the magnetism because of their alignment? Which is it, the...

Homework Statement Consider the following Z tranform X(z)=\frac{z^{-1}}{1-2z^{-1}+2z^{-2}} Calculate the poles and resides by hand. Homework Equations To find residue at pole p1 (z-p_{1})X(z)z^{k-1} Evaluate at z=p_{1} The Attempt at a Solution OK so I've taken the X(z)...

Homework Statement Find the residue at each pole of zsin(pi*z)/(4z^2 - 1)Homework Equations An isolated singular point z0 of f is a pole of order m if and only if f(z) can be written in the form: f(z) = phi(z)/(z-z0)^m where phi(z) is analytic and nonzero at z0. Moreover, Res(z=z0) f(z) =...

Why do the magnetic poles line up (relatively speaking) with the poles of Earth's rotation?

Hi, i'm having a bit of trouble understanding how a system modeled by a transfer function in the laplace domain with no zero's and a complex conjugate pair for the poles causes an oscillation when the unit step function is applied. Any help would be appreciated Many thanks.

as per the title. does anyone know?

If i know just these 3 values is it possible to implement a circuit using just OP-AMPS, capacitors, and resistors? How would I go about determining what values the capacitors and OP-amps should have? The circuit is a low-pass filter and thus needs to amplify and filter simultaneously.

Can anyone point me to a journal article that describes, mathematically or otherwise, how those jets shoot from the poles of some black holes with accretion discs and AGN. Also, if you will forgive the additional question, is there any reason why the physics that describe the ejection from...

Hi! I have a little problem. I have an exercise where it's said that the tranfer function gives 3 poles and the rank of the controllability matrix is 4. The question are: how many state has the sistem? Is it controllable? Is it observable? My solution were...the number of state is at...

I have two questions 1. The magnetic field around a straight conductor carrying current forms concentric circles around the magnet. Where are the north and south poles of this magnetic field? 2. Can a permanent magnet be made to generate a magnetic field similar to that of a wire carrying...

A study, accepted for publication in the journal Astronomy & Astrophysics, says ESA’s Herschel Space Observatory has spotted a young sun-like star 750 light-years from Earth that is shooting water from its poles at about 124,000 miles per hour. I wonder, do all protostars do this? Is oxygen...

Hi Everyone, I have made a solenoid of 100 turns. When i bring a small permanent magnet near the solenoid, it attracts the North pole of permanent magnet while it should attract the South pole according to right hand thumb rule... now i got confused. Kindly help me. Regards, hsn

Homework Statement In control engg. we define the order of the system as (or atleast as far as I have understood as) Nu/s^m*(s+a)(s+b)... I cannot understand the base for such classification? Why are we classifying systems based on the number of poles they have on origin? Homework...

my book on prime numbers has a line where it skims over a residue computation, and I am in dire need of clarification. It's rather simple, and I may very well be the one mistaken, but I am getting a extra factor of 1/2 in the residue whereas in the book it does not appear and apparently isn't a...

Kind of stuck (embarrassingly) on determining what poles of the function: 1/(z^6 + 1) lie above the y-axis (I'm solving a contour integral using the residues theorem). What's the easiest way to do this? Normally I'd write z as e^(theta + 2kpi)/6 , where theta is the angle that -1 forms...

Not meant to be a homework question, but since I don't have any valid data on hands so I am hesitate posting this in classical physics forum. The headline suggests the opposite of what we physics tell us. But my question is, is it theoretically possible to make like poles attract (assuming no...

Pretty simple question here guys, but I can't get my head around it. When solving say, the Greens Function for the driven harmonic oscillator, one needs to use the Residue method of integration. So, one adds a complex quantity to your variable w (angular frequency), so we now have w ---> w +...

Homework Statement A PMAC machine is connected in Y and has 4 poles. I_F\,=\,27\,A and L_m\,=\,20\,mH. a) It is to operate at a torque of 35 Nm and at a speed of 4000 RPM. Calculate the necessary stator current I_S and voltage V_{S\,line-to-line} so that the losses are minimal. b) If the...

If f(z) and g(z) share all the same poles, is f(z)-g(z) pole-free? I feel like this would be true, but I can't really come up with a proof for it.

Say I am integrating some algebraic function with respect to a variable q. There is also an exp( iq ) in the integral as a factor. There are poles when q takes a certian value as it is in the denominator as q - A, so pole at q = A.I know the poles are in the upper left plane, and lower right ...

Homework Statement Heres the question, I honestly don't know where to even begin :( An AC model of a cascode common-source amplifier is shown below. M1 and M2 are biased in saturation mode. The parasitic capacitors in the transistors are included. Determine the poles in frequency response...

Hey guys, i have the following situation: I have a function which looks like \frac{(a+bx)^3}{(x-y)^6(x-z)^6} As one can easily see this function has poles at y and z of order 6. Now, I know how to calculate the residue of this function for instance at y, but how do I implement this into...