Path Definition and 1000 Threads

  1. .Scott

    B Myth: When you toss something, air aside, it follows a parabolic path

    Actually, the path can be precisely parabolic, but you will need quite an arm to get that result. More commonly, the path will be a section of an ellipse - one that terminate when it hits the ground. In general, it will be a segment of one of the conic sections.
  2. Tareq Naushad

    I Free electron path without a nearby proton

    In absence of a positive electric field created by proton what type of behavior an electron shows? I am talking about a free electron like from a electron gun in deep space . Pauli's exclusion, orbitals, energy level etc. which are normal in an atom for electron will be absent for an electron...
  3. Mary Conrads Sanburn

    COVID-19: The Path Forward - How the Science Will Drive Recovery

    COVID-19: The Path Forward - How the Science Will Drive Recovery https://www.youtube.com/results?search_query=Covid-19-The+Path+Forward-How+the+Science+will+Drive+Recovery
  4. JD_PM

    I Understanding how to derive the Feynman rules out of the path integral

    I am studying interacting scalar fields (from Osborn) using the path integral approach. We define the functional integral \begin{equation*} Z[J] := \int d[\phi] e^{iS[\phi] + i\int d^d x J(x) \phi(x)} \tag{1} \end{equation*} The idea is to differentiate ##Z[J]## with respect to ##J## and end...
  5. Traced

    Determine the speed and tension of keys swinging in a circular path

    a)Determine the slowest speed that the keys can swing and still maintain a circular path. Fnet = Fg + Ft Fc = Fg + Ft When Ft = 0, Fc = Fg So, Fc = mv^2 / r and Fg = mg mv^2/r = mg v = √gr v = √9.81 * 0.25 v = 1.56 m/s Therefore, the slowest speed that the keys can swing and still maintain...
  6. E

    B Interpreting Path Ordered Exponentials with Non-Sensical Integration Variables

    I see a term like$$\int_0^{t''} \left[ \int_{t'}^t \omega(t'') \omega(t') dt' \right] dt''$$here ##\omega## is a matrix. How to interpret this integral - the integration variables are in the limits, in places where they don't make sense. Is that a mistake? It's given that the range of...
  7. M

    Path Integrals in Wolfram Mathematica

    Hello everyone ! I am new to this site so I 'd better say hello to you all ! I am finishing my BR in physics and part of this ending is to deliver a thesis . Long story short I must compute path-integrals in SU(2) and SU(3) pure yang-mills fields . Problem is that i was never very good with...
  8. M

    MHB Find path to minimum cost from start to finish

    Hey! 😊 I am looking the following: The board of a game is an $M \times N$ board with squares, where the starting point is on left - in position $(0, 0)$ - and the finish is in the lower right - in position $(M-1, N-1)$. Each square contains a positive number that describes the cost of moving...
  9. SadPaul

    Comp Sci Shortest path problem in bipartite graph

    Hey guys, I need a little help with this exercise so I know I'm on the right path. My explanation: The Bellman-Ford-Moore algorithm computes shortest paths in O(nm) time, so in this situation we say that in a directed bipartite graph the number of iterations that the algorithm will do is...
  10. cle102

    Uniform Circular Motion: banked race track circular path

    Basically, I need help to continue on this question. This is what I have now: Angle of the race track (angle of the grey part): tan(18/(169-108)) = 0.30396 Not sure how to continue?? What am I supposed to do and find next? Thank you in advance! :smile::blushing::oldbiggrin:
  11. madafo3435

    Understanding Short Circuit Current Paths in Electrical Circuits

    My reasoning is as follows: with the short circuit present, a 0 resistance can be considered between the terminals. Then, since the only objective of the short circuit current ##I_{SC}## is to give information about the Thevenin equivalent resistance and the open circuit voltage (the existence...
  12. WonderKitten

    I Multivariable limits - path problem

    Hey, so I have the following problem: I'm trying to prove that the limit doesn't exist (although I'm not sure if it does or not) so: along y=mx -> x=y/m: , which is 0 for all k≠0. along y^n it's the same and I'm not sure what I should do next. Could I set x = sin(y)? If I can, then the limit...
  13. A

    Electric Circuit: Path of Least Resistance

    I figured that when you close the switch the current from the upper cell will travel through the closed switch due to it being the path of least resistance, essentially the resistor between cells is unused (was my first thought). I'm not entirely sure how to progress with this question.
  14. Mircro

    Radio waves in air and water - difference in path

    Hello, this is an assigment form the 4th grade high school physics in Croatia, concerning electromagnetic waves. Radio waves of wavelength 12m propagate from the source. The source is on the surface of the water and two waves propagate from it: one through the air and the other through the...
  15. danielhaish

    I Would light keep on a straight path after it bends?

    I am asking this question because I dint find a source that explain why the light go in straits line Let say that a light go near very big mass that bend it ,and then the light escape it . would the light change his angle after it band like that the red part is the range where the mass effect...
  16. PORFIRIO I

    A Where did this term in the path integral come from?

    I'm trying to derive the path integrals, but this step got me confused: Consider the propagator $$K_{q_{j+1},q_j}=\langle q_{j+1}|e^{-iH\delta t}|q_j\rangle $$ Knowing that ##\delta t## is small, we can expand it as $$K_{q_{j+1},q_j}=\langle q_{j+1}|(1-iH\delta t-\frac 1 2 H² \delta...
  17. cianfa72

    I Check for geodesically-followed path in a coordinate-free way

    Hi, My question can result a bit odd. Consider flat spacetime. We know that inertial motions are defined by 'zero proper acceleration'. Suppose there exist just one free body in the context of SR flat spacetime (an accelerometer attached to it reads zero). We know that 'zero proper...
  18. F

    Python Why is a temporary directory created when using the Python library matplotlib?

    Hello, I am getting better at using the command line in Windows. I understand that the "set" command at the prompt shows all the various environment variables, PATH variable included, and I see many directories listed in the PATH. However, when I access the environment variables through the...
  19. jedishrfu

    A Great Tragedy Looms: Mt Wilson Observatory is in the path of Bobcat

    https://laist.com/2020/09/15/mt_wilson_observatory_bobcat_fire_hubble.php
  20. B

    I Muon Time Dilation in Accelerating Frames

    Hi In the book, "Why does E= mc2" by Cox and Forshaw, while discussing time dilation, the example of a muon is given. The authors explain that muons when circulated in the 14 m diameter AGS facility at Brookhaven at 99.94% of the speed of light, its lifetime is increased from the value of 2.2...
  21. jk22

    I How to find the photon's path?

    Let be given the ##\vec{E}(r,\theta,\phi,t)## and ##\vec{B}(r,\theta,\phi,t)## fields that are solution of Maxwell equations in vacuum. How to find the trajectory of the photons ? Is the photon moving along the Poynting vector, like ##\vec{S}=\vec{E}\times\vec{B}## at the speed of light ?
  22. AN630078

    Sound Wave Interference and Finding the Path Differences with Diagrams

    Question 1: a. λ=v/f λ= 340/85 λ=4 m b. Please see attached. Ihave tried to accurately and to scale construct a diagram representing the compressions and rarefactions of the sound waves. Since the wavelength of a wave is simply the length of one complete wave cycle, and I have found that the...
  23. I

    I What Do Phase Space Path Integrals Compute?

    I have heard of phase space path integrals, but couldn't find anything in Wikipedia about it, so I am wondering, what does it compute ? In particular, are the endpoints points of definite position and momentum? If so, how does one convert them to quantum states ? Also, how is it related to...
  24. cwill53

    Mean Free Path of Air Molecules

    I used the form of the mean free path equation taking advantage of the fact that the Boltzmann constant is equal to the ideal gas constant R divided by Avogadro's number, because I didn't know if I could use the Boltzmann constant in the ##1.381\cdot 10^{-23}J/(molecules\cdot K)## form...
  25. F

    Why does light take a longer path in a rarer medium?

    When traveling into an optically denser medium, the speed of light reduces and as per the principle of least time, light bends towards the normal and takes the shortest path. But why isn't this followed when light passes into a rarer medium? With its speed increased in the rarer medium, if it...
  26. hyksos

    A Derive the Principle of Least Action from the Path Integral?

    Several weeks ago I had considered the question as to how one can start from the Schroedinger Equation, and after several transformations, derive F=ma as a limiting case. At some point in my investigations of this derivation, it occurred to me that this is simply too much work. While in...
  27. E

    Which engineering path should I follow?

    How did you find PF?: Google Hi, I am very undecided and confused about what engineering path(I don't know if I should say path or field) I should follow, so I am here to get some information about each engineering path. At first, I was interested in biomedical engineering, but then I changed...
  28. R

    I Hamilton path and circuit rounded path problem

    Here is a graph. I wonder if it has hamilton path or circuit. In hamilton path we have to cross once and only once at an edge, and the start and the finish must be different locations. In hamilton circuit we have to start and finish the same edge. So the circle which B is rounded, which kind of...
  29. HexHammer

    B What Is the Occurrence Rate of Path Integral in a Photon Double-Slit Experiment?

    Hi forgive my very ignorant question. How frequently does 'Path Integral', curved shot and normal shot happen out of say 100 shots with a photon?
  30. mcastillo356

    Path of an electron from the Sun to the Earth

    Let's suppose a solar electron moving directly towards Earth's equator at a high speed. This electron meets Earth's magnetic field, which points to the north, at a distance ten times the Earth's radius, where magnetic field is almost uniform. Which will be the direction this electron describes...
  31. J

    Studying Need help getting started on my path to University

    Hello everyone I hope this is an appropriate place to post. It will be two years until I can attend university and I have some questions. I have developed a love for math and more recently physics and am sure this is the path that I want to take at university. To give you an idea of what I mean...
  32. E

    Question about variations of the Sun's path over long periods of time

    Hello. I am a filmmaker writing a screenplay and I am in need of technical support to validate a method being used in the film. I am going to post this in the Earth Science forum but I'll copy it here, in case anyone reading this might know. Thank you all! "I am wondering if shadows cast...
  33. E

    Path of light in material of continuously varying refractive index

    I've been playing around with this for quite some time now this morning but can't get the last bit out. I defined the time functional to be $$T[y] = \int_{x_1}^{x_2} \frac{\sqrt{1+(y')^{2}}}{c(y)} dx$$ which follows from consideration of the time taken to cover an infinitesimal section of arc. I...
  34. danielhaish

    Behavior of one electron choosing a path

    I know that current chose the way with the lowest resistance but this is becouse that few electrons will go on the two path and the smallest number of electron .,Is the path that the current go throw . But how does a single elelctrons "choose" is path . And also if I connect two wire to a...
  35. F

    Determining the path of a particle in a field

    This is not a specific homework question, but more of a general query. If provided with a simple vector field indicating forces (for example, an electrical field), can you use integration to determine the path of a particle placed in that field, if also provided with some initial conditions...
  36. Kevin Chieppo

    Physics Career path forward for a physics autodidact?

    Hi, everybody. I did an undergrad in computer engineering, and am currently happily in a software development position, but I've always had a passion for physics and could see myself loving being in a position where I'm working in clean energy. I've spent lots of free time learning about and...
  37. M

    Work done by a force along the path

    If the first equation for force is not formatted please refer to the pic. I did not post my full attempt as the problematic equation leads to a complex integral. Should I be converting r vector into its univector. The two outlined equations refer to the force. I am making an error transforming...
  38. kolleamm

    Other Computer Science Career Path Help

    Hi everyone, Recently I finished my Bachelors in Computer Science, and since then I've been mostly stuck thinking were to go next from here. I've applied to a lot of software jobs online but haven't had any luck. It seems to me that although what I learned in school seems useful, things such as...
  39. W

    I Propagator of a Scalar Field via Path Integrals

    I don't understand a step in the derivation of the propagator of a scalar field as presented in page 291 of Peskin and Schroeder. How do we go from: $$-\frac{\delta}{\delta J(x_1)} \frac{\delta}{\delta J(x_2)} \text{exp}[-\frac{1}{2} \int d^4 x \; d^4 y \; J(x) D_F (x-y) J(y)]|_{J=0}$$ To...
  40. Decimal

    A Path between fixed points in a logistic map

    Hello, I have a question about period doubling and fixed points in the logistic map. Let's say I have a basic logistic map, ##f(x) = 4\lambda x(1-x)##. Let me then compare 1,2 and 4 iterations of this map on fixed points. I assume that ##\lambda## is large enough such that two period doublings...
  41. CrosisBH

    [Computational Physics] Modeling the path of a Baseball with drag

    import matplotlib.pyplot as plt import numpy as np #constants and conditions initial_velocity = 49.1744 #m/s, book has 110mph velocity_angle = 35 * np.pi / 180 #coverted to radians because numpy only likes radians gravity = 9.8 #m/s^2 dt=0.1 windspeed = 4.4704 #m/s book has 10mph #calculating...
  42. K

    Electron path in the presence of a dielectric

    Hello! Assume that I have a parallel plate capacitor. If i place an electron close to the negative plate, it will move in a straight line (and accelerate) towards the positive plate. Now, assume that I place a neutral dielectric close to the electron trajectory (parallel to it), say at 1 mm away...
  43. S

    Which path in physics do you prefer: Theorist, Experimentalist, or Educator?

    Poll Question:Suppose your working on your graduate degree in Physics. You can go either be a Theorist or Experimentalist, or Education or Research. Which path would you select?"Years of hate will turn the hated into a hater."Choices: Theory, Education Theory, Research Experiment, Education...
  44. Z

    How can I solve the projectile motion without finding the equation of the path?

    This is a projectile in which I can solve, IF they didn't ask to find the eq. of path. I need any help possible with this one please...See a pic of the prob by clicking herehttp://www2.livemath.com/livemathboard/files/152744283/LM152744283-1998364165.jpg
  45. M

    How Does a Photon Determine Its Straight Path After Leaving an Atom?

    We are taught that light travels in stright lines when ever it can. My question is when a photon has left its captive atom how does it know which way is straight?rm
  46. F

    Is Becoming a Physicist the Right Career Path for You?

    i took a preview of the sat test and they allow you to choose a proffesion and they would give some information about it. well guess what? i picked physicist!here is the information i recieved, its not that long, enjoy...
  47. M

    Can Electro-Static Fields Bend the Path of Light Waves?

    Hi everyone,Here's an simple idea that I've come up with.If lightwaves can be modeled as a particle which is continually changing it electro-static charge ( osilating between postive and negative charge ), then should we be able to bend the path of lightwaves with electro-static fields?e.g.Get...
  48. R

    Path integral & statistical problem

    Hello all,I don't really understand what's connection between path integraland statistical mechanics. When we give the following expression ofpath integralintegrate{ Dx(t) exp(i S[x] / hbar) }does it mean the expression can only apply to a single particle. Howabout if we use the above expression...
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