Diagrams Definition and 689 Threads

A diagram is a symbolic representation of information using visualization techniques. Diagrams have been used since ancient times on walls of caves, but became more prevalent during the Enlightenment. Sometimes, the technique uses a three-dimensional visualization which is then projected onto a two-dimensional surface. The word graph is sometimes used as a synonym for diagram.

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  1. M

    Velocity / Acceleration Diagrams of a Mechanism - Piston and a rotating rod

    Summary:: This is a question about finding the acceleration of a point in a mechanism Hi, I have a question about the mechanism shown in the attached picture: Question: We are told that \omega = 6 rad/s and the first part is asking me to find the acceleration of point P on the piston when...
  2. F

    Irreversible cycles, Carnot's Principle and volume-pressure diagrams

    Hi all, this question is related to a similar one I posted a couple of weeks back. Please keep in mind that the level here is high school. I'm looking for a way of describing the concepts in the title that is not overly technical. I keep circling back to these concepts because it seems to me...
  3. R

    I Calculating a particular amplitude with Feynman diagrams

    So I’m trying to compute the probability amplitude of an electron with momentum p1 and a positron with momentum p2 annihilating into a photons with momenta q1 and q2. My question is how do you use Feynman diagrams to calculate the first and second order expansions (seen in the third image)? I...
  4. Like Tony Stark

    Free body diagrams for boxes, inclined planes and springs

    FIRST PICTURE I have some doubts here because of the spring... I'll tell you what forces I've drawn. For ##A##, I drew the weight and the force applied by ##B## (the normal force) on the vertical axis; and the elastic force pointing to the right on the horizontal axis. For ##B##, I drew the...
  5. N

    B Understanding Spacetime Diagrams

    I got the book "An Illustrated Guide To Relativity" by Tatsu Takeuchi, and have questions on how to understand spacetime diagrams from different reference points. Before I ask, please let me know how I can draw a spacetime diagram and post it on the forum. I will want to use different colors to...
  6. A

    A Feynman diagrams strong process

    Hello everybody! I have to write the Feynman diagrams for the process ##\pi^- + p \rightarrow \Lambda_c^+ + D^-##. It is a strong process since all the quantum numbers are conserved. I have attached my attempt, is it correct? Thank you all in advance!
  7. D

    B What are Feynman Diagrams and how do they help explain Quantum Electrodynamics?

    I'm new to QED, so I want to have a general grasp of what's going on. I just want to understand it conceptually. Can anyone explain it in a way so a layman can understand?
  8. K

    I Usefulness of Diagrams for Relativity: 1-5

    On a scale of 1 to 5, how useful do you think are diagrams for understanding / studying special relavity? What about general relativity?
  9. DanielMB

    I Implication, Boolean Expression and Venn Diagrams

    Hello, I’m having difficulties understanding logical relations “A implies B” and “A if and only if” using Boolean expressions and Venn diagrams, there is something where I’m wrong, but I could not find it out. Please, be benevolent and tell me where I’m wrong. Thanks Note : Obviously I’m...
  10. Mcp

    Phase diagrams for fractional distillation

    https://www.chemguide.co.uk/physical/phaseeqia/idealpd.html#top I learned about phase diagrams involving partial Vapour composition, temperature and composition of binary solutions from this website. You can find it if you scroll down to a little above the end First it considers a binary...
  11. Benjamin_harsh

    What are the names of these "F" arrows in these three diagrams?

    What is the names of this "F" arrows in this three diagrams?
  12. A

    Amplitude with Feynman diagrams and gluon propagators

    The term which is relevant for the calculus is: $$ \bar u(p) \gamma^\alpha \frac{1}{\displaystyle{\not}p+\not k} \gamma^\nu \frac{1}{\displaystyle{\not}p'-\not k} \gamma^\beta v(p') \frac{k_\alpha k_\beta}{k^2} $$ $$ \bar u(p) \displaystyle{\not}k \frac{1}{\displaystyle{\not}p+\not k}...
  13. A

    LaTeX Excluding circuittikz, how can I create circuit diagrams

    Hello. I want to create circuit diagrams, excluding the package tikz and not wanting to write up a schematic in latex, how can I create circuit diagrams? I would think one of you would have been creating and importing complex diagrams into latex. I do not want to take pictures and post them, I...
  14. P

    I Understanding Band Structure Diagrams

    Hi! I never really understood band structure diagrams. I think they represent the energy of an electron, with the given circumstances, at a k vector. Are the electrons only allowed to be on the lines here? Or can they also be in areas enclosed under/between certain lines? What are some...
  15. fluidistic

    Solid State A guide to Feynman diagrams in the many-body problem

    I'm trying to go through Mattuck's book "A guide to Feynman diagrams in the many-body problem", the Dover's 2nd edition book. I have read that apparently it has been criticized for being way too easy. I'm having an extremely hard time going through the 3rd chapter, let alone the 4th! I feel...
  16. P

    Reading optics diagrams: Glan-Taylor

    Hi everyone. This isn't for a class but more for lab work. I'm confused on how to read optics diagrams to understand this Glan-Taylor prism, specifically the up and down arrow vs the dot. Does the arrow pointing up and down mean that it is vertically polarized. Is the dot horizontally polarized...
  17. F

    I Complete list of Feynman diagrams

    Is there an on-line list of all possible Feynman diagrams for all the known particles?
  18. C

    I Explicit computation of mass counter term diagrams

    In most treatments of the mass renormalisation in dim reg, I see sources find the mass counter term by extracting the coefficient of e.g the ##m^2## term accompanied by a pole in epsilon. I know the mass counter term is found by placing an X on diagrams where there is usually a self energy...
  19. S

    Programs Will my horrible drawing skills hurt me as a physics major?

    I'm going to return to college starting Fall, 2019 as a physics major. In preparation, I've been going though various textbooks, studying the material and working the problems. The concepts I understand reasonably well. The problem? I'm horrible at drawing. I see some problems, especially in...
  20. M

    I Using a bifurcation diagrams and time dependent parameters

    Hello, I'm lost at where to go after drawing bifurcation diagram of $$\dot{x} = r + x - x^3.$$ If we also assume our parameter is time dependent such that $$\dot{r} = -\delta x.$$ How could we use our initial bifurcation diagram to sketch solutions for small δ?
  21. Ramtin123

    A Computing amplitude for divergent loop diagrams?

    I am trying to compute the cross-section for the diagram below with a divergent triangle loop: where ##X^0## and ##X^-## are some fermions with zero and negative charge respectively. I am interested in low energy limits, so you can consider W-propagator as ##\frac {i\eta_{\mu\nu}} {M_w^2}##...
  22. Cerenkov

    B What are these diagrams showing about GR?

    https://universe-review.ca/I02-24-inflation2.png https://courses.lumenlearning.com/astronomy/chapter/the-inflationary-universe/ http://abyss.uoregon.edu/~js/ast123/lectures/lec18.html Hello. The diagrams I've linked to are comparisons between the Standard Hot Big Bang and Inflationary...
  23. D

    I have to work out Fault MVA and draw impedance diagrams

    Homework Statement For the system shown in FIGURE 2, using a 10 MVA base, calculate the fault MVA levels through each unit and the base "voltage" MVA across each unit for a fault at F. Draw the impedance diagrams showing the fault levels and the base "voltage" MVA across each unit for: (a) bus...
  24. opus

    Constructing accurate diagrams of word problem- Trig

    Homework Statement A canoe is floating down a creek. The canoe is first spotted 80 feet away. 7 minutes later the canoe is 45 feet away, making a 40° angle between the two sightings. How far did the canoe travel? Homework Equations Law of Sines and Law of Cosines The Attempt at a Solution...
  25. P

    A The Optical Theorem for Feynman Diagrams

    In Peskin's textbook section 7.3 The Optical Theorem for Feynman Diagrams(Page233), he said it is easy to check that the corresponding t- and u-channel diagrams have no branch cut singularities for s above threshold. But I can't figure out how to prove it. Can angone help me? Thanks!
  26. D

    I Can Diagrams be Used as Circuits in Explaining Sensor Operations?

    I have to construct suitable circuits to show the operational principles of some sensors: pH meter, sound, light and temperature. Would these count as circuits? or diagrams? (I'd say diagrams). https://www.electronics-tutorials.ws/io/io45.gif I am finding it hard to find circuits showing how...
  27. Biker

    Liquid-solid phase composition: Binary phase diagrams

    In binary phase diagram, We draw a tie line to know the composition of the liquid phase or the solid phase. Where the tie line is just a horizontal line. The question is why doesn't the liquid or solid phase composition change as you change the general composition of the alloy? Why does the...
  28. Peter Alexander

    Understanding Transformer Phasor Diagrams

    Hello everyone! I'm currently studying transformers and a task related to phasor diagrams shows up. I'm having lots of problems with comprehension of the subject, so I'd like to ask for some help. I don't understand how the phasor diagram given as a solution could possibly be drawn out of the...
  29. lc99

    Understanding PV Diagrams: Analyzing Work, Heat, and Temperature Changes

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] I was wondering if the answer is all statements are true. I want to know if my reasons are correct: 1) the work done by the system is greatest along path 1 because work done is equal to the area under the path. The path...
  30. dRic2

    Francis diagrams and Acetaldehyde?

    Hi, my professor asked a friend of mine to draw the line for Acetaldehyde in the Francis diagrams. How can someone answer that question without knowing ##ΔG°(T)## of Acetaldehyde? Are there some qualitative consideration that can help me draw an approximated line ? For example I thought that...
  31. S

    Circuit Diagrams versus Logic Diagrams

    Why do we sometimes neglect resistors and power sources when we draw circuits and other times not? Is there different terminology for diagrams that are only concerned about the logic involved and diagrams where the voltage and resistance is accounted for?
  32. C

    A How to relate the expansion term to Feynman diagrams

    I learn quantum field theory using the book of " quantum field theory in a nutshell" by A. Zee. But I am confuse when I read the content about the "baby problem" at the beginning of "1.7 Feynman Diagrams". In that section, author get the term of order λ and [J][/4] by -(λ/4!)[(d/dJ)][/4]...
  33. M

    Feynman Diagrams for Interacting Scalar Fields

    Homework Statement Consider four real massive scalar fields, \phi_1,\phi_2,\phi_3, and \phi_4, with masses M_1,M_2,M_3,M_4. Let these fields be coupled by the interaction lagrangian \mathcal{L}_{int}=\frac{-M_3}{2}\phi_1\phi_{3}^{2}-\frac{M_4}{2}\phi_2\phi_{4}^{2}. Find the scattering amplitude...
  34. N

    MHB Conditional Probability and Venn Diagrams

    I am having a hard time with the following exercise: Assume for this problem that the company has 8 Chevrolets and 4 Jeeps, and two cars are selected randomly and given to sales representatives. What is the probability of both cars being Chevrolets, given that both are of the same make? I...
  35. lc99

    Understanding 3D Diagrams for Solving Angle Problems

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] I am having trouble visualizing the 30 degree angle? How would i know that it is in between 2 planes and not just 1 plane. I thought it would be in the x/y plane. In cases like this where they should you the angle (arrow) to...
  36. P

    I Virtual particles in Feynman diagrams

    In the first diagram above, if I understand it correctly, the photon turns into an electron positron pair and then back again to a photon. However, what exactly is happening in the second diagram at the bottom left hand corner? Is the electron being converted to an electron photon pair?
  37. P

    I Calculating the fine structure constant in Feynman diagrams

    Griffith's Introduction to Elementary Particles, if I understand it correctly, states that in QED, the fine structure constant contributes less and less to the strength of the EM interaction as we add more and more vertices since the constant is so small (1/137). However, in QCD, since the...
  38. U

    Applied Book recommendations for Bifurcation Diagrams

    Hello my friends, I am studying excitability in quantum dot lasers and I see a lot of bifurcation diagrams with saddle node bifurcations, Hopf bifurcations, homoclinic bifurcations, PD bifurcations etc. I know some basic things about non-linear systems but I have never met the notion of...
  39. thebosonbreaker

    A question about Newton's laws & free body diagrams....

    Here I have drawn the free-body diagram for a rock (but could really be any object) which is being pulled upwards. Fa represents the applied force (let's say...by a rope) Fg represents gravity/weight of the object Ff represents friciton, i.e. the small amount of air resistance But here's my...
  40. P

    Best software for block diagrams?

    Hi - I need/want to create reasonably professional block diagrams and wondered if anyone knew of the best software to do this? Free is better than $$ unless the stuff you pay for is loads better. We are not talking anything amazingly complicated here. I am doing some work with optics and...
  41. K

    I Designing a Car with Multiple Boxes: Free Body Diagrams

    hi, i am studying about design the box carried on car. i am really stuck in how to draw free body diagram for when 3 or more boxes stack together on car running and braking. there are many example with 2 boxes but i don't know why i can't find any case with 3 or more boxes thanks in advance
  42. F

    Sheer and bending moment diagrams

    ok so for concentrated loads the sheer diagram is constant meaning are straight horizontal lines and the bending moment diagram is linear. when there are evenly distributed loads sheer diagram is linear and bending moment diagram is quadratic. I am thinking that when there is a load distributed...
  43. P

    How to improve handwriting and diagrams

    I'm currently doing my B.S. in physics with a minor in education, with the intent of becoming a public high school physics teacher. So far I haven't had any major issues with any of my coursework, but I do have one problem: my handwriting and drawing skills are terrible! As a teacher, I'm...
  44. O

    A Question about QFT Diagrams and their Integrals

    I am studying the terms in the dual Taylor expansion of Z_{1}(J) in \phi^{3} theory, and being introduced to Feynman diagrams in the process. I thought I would try to simplify one of the terms in the expansion so that, after taking derivatives of all the sources, I ended up with integrals that...
  45. D

    Understanding e+e- --> W+W- Process Diagrams

    Homework Statement Hi there, I am a very beginner in particle physics and now I'm struggling with this question. Draw the lowest-order Feynman diagrams for e+e- --> W+W- process Homework EquationsThe Attempt at a Solution There are 3 answers as follows: Q1: 1st pic: Why did the gamma and Z...
  46. D

    How do I draw Lewis Structure Diagrams? +1 More

    Homework Statement : 2 Questions, sorry about this if It adds confusion. 1) How do I go about drawing Lewis Structure Diagrams? I've searched the web, but all I can find, even when they say it's a "Lewis structure" diagram is lewis dot diagrams. My teacher wants it in the specific form where...
  47. M

    Forces and Free-Body Diagrams in Real-World Scenarios

    Homework Statement I am just going over my class notes and I just wanted to clear up a few concepts regarding forces and free-body diagrams -- I'm either missing some forces or adding one too many: Identify the forces acting on objects in each of the following situations and draw a free-body...
  48. M

    Engineering Analyzing currents in parallel in circuit diagrams

    Homework Statement Homework Equations V=IR parallel resistance. The Attempt at a Solution All elements are in parallel (teacher confirmed this in explanation to the class). Beginning placing labels for nodes to the right of R1, A, B, C, D, and E (ending before R4) and redrawing it as the...
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