Loop Definition and 1000 Threads

How would you go about calculating the work done in morphing a square current-carrying loop into a circular current-carrying loop, without change in length while maintaining the same angular orientation with an external magnetic field. My book suggests defining P(potential energy) = M.B (dot...

To be honest I am a bit clueless first with how to interrupt this question I think the bead is going around a wall type thing where there is friction both in the up and X direction. Some hint to get some ideas running would be great

I can evaluate the first beads motion easily A to B is -2Rj considering the point B as y=0 the motion of the bead will be -gt^2/2+2R=0 which implies t=2√(R/G) , this is ok but what I am struggling with is A to C I can see that the angle between the beads weight and it's negative normal force...

The energy stored in a current loop equals ##\frac{LI^2}{2}##. From a dimensional argument, it follows that the inductance grows with the size of the loop. This would mean that, if we assume the current stays constant, enlarging the loop would require external positive work, so, the force...

Last week I encountered a problem in my graduate project. The project was about designing an autonomous and mobile robot that picks up 9 glass tiles from a stack point and place them into a 3x3 matrix with minimum tolerance. I am using a DC motor with an infinite turn potentiometer for closed...

Hi All I'm learning python and have never seen a for loop positioned like this: integers = [4, 5, 7] strings = [str(integer) for integer in integers] I've only ever seen for loops positioned at the beginning of lines. Is this usual? How can I know when this is okay? I think I would have tried...

I am stumped and would like a hint. Answer choices:

Suppose we are give a homogenous hollow cylinder or "normal" dimensions (for example 3" inside dia., 4" outside dia., 5" high". The composition is any non-exotic, non-magnetic, solid material. Is there any way to cause it to rotate about its vertical axis? Whatever the material is, any...

Hello everyone, I have trouble installing Package-X 2.0 to Wolfram Mathematica. It says that the package should be available at https://packagex.hepforge.org but this page does not open. I tried everything I could to install and load this package but it was all unsuccessful. It seems as the...

\newcommand{\printNum}[2]{% #1 #2% } \newread\readEng \newread\readEsp \newread\readLineNo \newcount\myLineCount \myLineCount=0 \newcommand{\printNumRow}{\loop\global\advance\myLineCount by 1\read\readEng to \Eng \read\readEsp to \Esp \printNum{\Eng}{\Esp}\ifnum\myLineCount=\linenum...

I used the voltage of the power supply and resistance to solve for the current in the larger circuit (20V/5ohms=4 amps). I am not sure if the equation listed above is the correct one I should be using, but I tried it using the following numbers. For omega, I used 2*pi*frequency. N should...

I’m totally lost and struggling to understand my lecture notes. Can somebody point me in the right direction?

Hi, I had one or two questions about the operation of a PLL, which refer to the diagrams below - a control representation of the system and a diagram of the low pass filter circuit. Questions: 1) What is the point of having another (low-pass) filter ## G_f (s) ## for ## V_o ## after...

My understanding of the n-correlation function is \begin{equation*} \langle \phi(x_1) \phi(x_2) ... \phi(x_n)\rangle = i \Delta_F (x_1-x_2-...-x_n) \end{equation*} Where ##\Delta_F## is known as the Feynman propagator (in Mathematics is better known as Green's function). Let us analyze...

My attempt at this: From the general result $$\int \frac{d^Dl}{(2\pi)^D} \frac{1}{(l^2+m^2)^n} = \frac{im^{D-2n}}{(4\pi)^{D/2}} \frac{\Gamma(n-D/2)}{\Gamma(n)},$$ we get by setting ##D=4##, ##n=1##, ##m^2=-\sigma^2## $$-\frac{\lambda^4}{M^4}U_S \int\frac{d^4k}{(2\pi)^4} \frac{1}{k^2-\sigma^2} =...

This should be pretty straightforward and my take gives B = 0.000193*T for a) and B = 0.00000063 T for b). Or have I misunderstood something?

Hello, I understand that a ##for## loop is intended to repeat the same code a finite and specified number of time. The loop syntax is for i in iterable: statement(s) for = keyword i = counter variable iterable = any iterable (list, tuple, dictionary, range()) statements = body of the...

Hey guys, I've started to read some OpenMP programming and now I'm trying to parallelize small part of a fortran code. The first thing I would like to do is to parallelize the innermost DO loop. It loops through the number of particles (na) and calculates the distance between some point in 3D...

The test case for the block of code below is: y0=10, f=@(t,y) -0.5*y, [t,y]=euler_method_attempt(f,0,5,y0,10) This code below works and is the correct answer, but I am confused on some parts of it. When indexing the for loop it seems as if the first output for "y" would be y(2), not y(1). And...

I have a problem understanding what is going on in the region called the ergosphere of a "fast" Kerr black hole. - Relativity teaches us that no frame of reference can have relative displacements greater than the speed of light, ok. - The ergosphere of a fast Kerr black hole can contain light...

%Debeye theory Heat Capacity of Copper %Garcia Problem 10.16 %Find molar heat capacity from 0-1083K (melting point of Cu) k = 1.38064852e-23; %Boltzmann's constant N = 6.02214e23; %Avagadro's number (atoms per mol) T = 0:1083 ; %Initialize Temp at 0K-1083K theta = 309; %Debeye temp of Cu (K)...

From the german Version of Carlo Rovellis book "La realtà non è come ci appare. La struttura elementare delle cose" I have learned about the theory of Loop Quantum Gravity that space and time arise through the interactions of gravitational quanta, the space quanta have discrete volume spectra...

Okay, so, the magnetic field lying(parallel) to the plane of the coil is confusing me quite a bit. Usually, in this kind of problem, we have a magnetic field directed perpendicularly to the plane. Considering this orientation of the field, wouldn't the torque on this sort of "elementary brush...

Hi all Physics Forum User, I am again coming to you to ask for help. For the above question I can't make sense of how a larger G will cause Vo/Vi to approach 1. For this I'll call Vo=V and Vi=I As can be seen from the control loop B = A*H and V = B*K hence V = A*H*K Also A = I - C and...

m_1 = 1; C_p1 = 2219; T_1in = 100 + 273.15; T_1out = 75 + 273.15; Q_1 = (m_1)*C_p1*(T_1in-T_1out); while Q_1 ~= 30000 T_1outnew = T_1out + 0.1; Q_1 = (m_1)*C_p1*(T_1in-T_1outnew); T_1out = T_1outnew; end T_1outnew keeps increasing, but the code never stops; and naturally, Q...

It's only a small PF shout out for my third novel, Handwavium, because it is more techno thriller than pure sci-fi story, so it didn't ask much from the collective brainpower of the forums. Still @Vanadium 50 and @stefan r gave their assists with gravitational wave triangulation, for which I...

If ##\tau= 0.0727, N=60, i=1.3, B=1.0,## and ##\theta=15##, I tried the following calculation: ##\tau=NIABsin\theta## ##\tau=NIs^2Bsin\theta## ##s^2=\frac {\tau} {NIBsin\theta}=\frac {.0727} {60*1.3*1*sin(15)}=0.0632 m=6.32 cm## The answer is probably right in front of me, but I don't know what...

Following the method by Peskin and Shroesder 11.4 Trying to calculate the vacuum energy of a fermion. If my method is correct so far the next step is to find gamma function , the formula I have for gamma fuctions doesn't match this equation. Can anyone help with the next step? Starting with the...

For this one circuit, I've applied Kirchhoff's laws as following: $$\left\{\begin{matrix} V-6\Omega I_{6}-24V-2\Omega I_{2}=0\\ 24V-6\Omega I_{6}-12V-24V=0\\ I_{2}+I_{6}=6A \end{matrix}\right.$$ but the values I get for ##I## and ##V## aren't correct... what's wrong?

Hello, In the following problem, when finding the equation for I2 I don’t understand why I3 is negative. Although I2 and I3 are going in different directions (clockwise and counterclockwise), at that ohm they are both going from left to right. When finding the equation of I1, I1 goes from left...

Hi, I was just working through a closed loop stability problem in Control Theory and I don't really understand how the answer has arrived at the solution so quickly. Problem: We are working with the closed loop transfer function: $$ P(s) = \frac{K(s) G(s)}{1+K(s)G(s)} $$, where $$ G(s) =...

Disclaimer: The solution to this question has already been posted by my instructor. I made this post to understand why my solution is wrong or if the instructor is wrong, since their explanation does not make sense to me. My reasoning: Using the fact that the magnetic torque on a...

I am trying to calculate the effective potential of two D0 branes scattering in Matrix theory and verify the coefficients in this paper: K. Becker and M. Becker, "A two-loop test of M(atrix) theory", Nucl. Phys. B 506 (1997) 48-60, arXiv:hep-th/9705091. The fields are expanded about a constant...

##\vec \tau = \vec \mu \times \vec B -eq1## ## F = I \vec l \times \vec B -eq2 ## The forces i have indicated The magnetic moment is coming out of the page. I am only attempting only the part (a) as of now a. The force calculations are F1 = 1.4*0.22*1.5 = 0.462 +X direction F2 = 1.4*0.22*1.5...

A new preprint establishes that almost all models implementing loop quantum gravity violate the principle of general covariance, and can only satisfy a more limited condition. Is this the huge problem for loop quantum gravity theory that it appears to be? Or is the less strict condition that can...

There’s a current i in the loop in the figure. The Ampere’s force iLB on a wire of length L exerts on charges in the wire but it does no work on the charges. The charges would go in circular motion if there were no wire. Then the wire exerts exactly iLB on those charges to keep the charges...

The height can be determined by conservation of energy (ignoring all friction). The mechanical energy when the car is at rest, equals the mechanical energy when the car is in the middle of the loop (at the top of the loop): \begin{equation} E_{0} = E_{loop} \\ mgh_0 = \frac{1}{2}mv^2+mgh_{loop}...

About this figure, the current in the opposite wires are parallel (and not anti-parallel). So, for instance for the first option the torque is zero; but I wanted to know what is the magnetic moment of this loop. Since I rely only on formula I've have no idea how to compute for this one.

I am having trouble figuring out if the circular loop has an induced current. One explanation is ∫ E ds = -d Φ / dt. Since flux = B ⋅ A, a change in the magnetic field would require a change in the magnetic field, a change in the area, or change in direction of either vector. Since none of...

Can anyone please tell me why the torque on a circular current loop can be calculated by the equation below? In other words, what is the intuition for the formula? Thank you. (I modified my question to a particular case) $$ \vec{\tau} = I \vec{A} \times \vec{B} $$

Hello! My homework is making a crossword. I write a code like this: do{ //code printf("Please enter the coordinate and the word: \n"); scanf(" %c%d %s",&row2,&column2,word2); if(row2=='E' && word2=="xit") exit(0); //code }while(count2!=10); But this is...

I haven't been on PF that long, and I mostly post in the Science Fiction section, but I have noticed in the "Writing and World Building" forum that few of us loop back after asking for help to let people know, "My novel is done". So, just to let you know, my novel is done and is live in the...

If the magnetic field is constant then no change in flux will bring no induced emf nor any induced current. With the loop is in rest position the external magnetic field will exert a force but to calculate that force with the help of magnetic field isn't obvious. If this were a charged loop, the...

I recognise that the normal force must alwayss act towards the centre of the circle loop, as the rail always has to be exertign a pushing force on the car/carriage in order for it to follow the trajectoryof the loop. However , I cannot understand why, the reaction force has to be greater than...

Given an EPR experiment such as the Alain Aspect 1982 test of non-locality using photons; if you modified the experiment so that the entangled photons first go through a analyzer loop (polarizer + inverse polarizer) before going to the polarizers in the experiment would you still see a non-local...

Good day all. Since the gradient theorem, also known as the fundamental theorem of calculus for line integrals, says that a line integral through a gradient field can be evaluated by evaluating the original scalar field at the endpoints of the curve. Then If we form the Gradient vector field...

As I understand it there have been different attempts to use LQG to make a theory of cosmology. The first one being done by Martin Bojowald and then later one being performed by Ashtekar, Pawloski and Singh. there is a description of what they did that was different but as a non cosmologist I...

I tried to solve the above i have one confusion here. I have marked the areas as shown B2 = B4 = 0; B1 , B5 Out of Page ; B3, B6 Into the Page. B1 and B5 Calculation Now main doubt is regarding the B field of the finite wire let us say 1. I took the derivation of the infinite wire as below from...