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.

View More On Wikipedia.org
Recent contents Top users
  1. S

    Showing Beta Decay (Feynman diagrams?)

    Would someone please tell me how I would show Strontium-90 decay into Yttrium 90(and emitting Beta particles)? Would I need to use a Feynman diagram? Thank you!
  2. C

    Question about Feynman diagrams with the integral

    I read the book of "quantum field theory in nutshell" by A. Zee. There is a "baby problem" in Page 44. I can't understand how to get the diagrams of Figure 1.7.1 from the calculation of -(\lambda/4!)(d/dJ)^4 differentiating [1/4!(2m^2)^4]J^8. How to associate this term to the three diagrams...
  3. Thor Shen

    From Feynman diagrams to potential

    I met a problem when I read the textbook "Relativistic Quantum Mechanics" by J.D.Bjorken. He said we can get the potential V(r_1,r_2)=\frac{f^{2}}{\mu^{2}}(1-P_{ex})(\tau_1\cdot\tau_2)(\sigma_1\cdot\nabla_1)(\sigma_2\cdot\nabla_1)\frac{e^{-\mu|r_1-r_{2}|}}{|r_1-r_{2}|} (10.51) from the...
  4. J

    Feynman diagrams and momentum conservation

    I understand that Feynman diagrams can be expressed either in the position or momentum representation. Is the 4-momentum conserved at the vertices in each case or only in the momentum representation?
  5. K

    Are these free-body diagrams correct (mass-spring-damper system)?

    Problem: Write the equations as a set of two, second-order ordinary differential equations. My attempt…does it look correct? Thanks in advance!
  6. M

    What is the Feynman diagram for Higgs decay to Z and gamma particles?

    Hi, I am drawing Feynman diagrams for various Higgs decay channels. There are two diagrams I am stuck on and there aren't many examples online. They are H→gg and H→Z\gamma For the H→gg decay I had a stab at drawing the reverse of the gluon fusion diagram. Higgs decaying to two gluons via a...
  7. B

    Draw shear force and bending moment diagrams

    Homework Statement For the beam shown in the figure: a) Draw necessary free body diagrams b) Calculate support reactions c) Draw the shear force and bending moments Homework Equations ∑Fy = 0; ∑M = 0; V(x) = ∫ L(x) ; M(x) = ∫ V(x) The Attempt at a...
  8. A

    Doubt on Fatigue Strength S-N diagrams

    A standard way of plotting an S-N (fatigue strength vs no of cycles) graph is to start off by taking a value of Sm (for N=1000) cycles and joining it to the point depicting Se(Endurance Limit). Now we commonly take Sm= 0.9Sut for steels. Now I was wandering, before you actually get to use the...
  9. C

    Need to learn how to make wiring diagrams

    I recently graduated with a bachelors in Mech Eng and have been asked to create some wiring and line diagrams for UL approved industrial control panels for my first job. I need some good resources to guide me through this... Any suggestions would be greatly appreciated. Thanks!
  10. U

    Drawing constant property lines on p-v/T-s/u-s diagrams

    Hi All, I'm really curious to know how we can predict the shapes of constant property lines (isenthalpic/constant internal energy/isotherms/isentropes/isobars) on any given plot, such as T-s and P-v or even u-s diagrams. Is there a rule to do so? Usually in practice we deal with p-v and T-s...
  11. A

    Best Programs for Creating Professional Lab Report Diagrams | Physics Forums"

    I wasn't sure which section to post this, I was going to put this in learning materials: https://www.physicsforums.com/forumdisplay.php?f=151 But it says I cannot post there...anyway, Are there any good programs, preferably free or inexpensive, that are useful for drawing professional...
  12. P

    Discover How to Select Internal Forces for Free Body Diagrams

    Homework Statement http://postimg.org/image/4lvunjeoz/ Solution: http://postimg.org/image/v1d7gilef/ When you have to calculate the internal forces at a point, how do you decide which forces are included in the free body diagram? For D, why isn't the rectangular bit of the distributed load...
  13. Q

    Understanding Phase Diagrams: Boiling, Melting & Critical Points

    Homework Statement https://scontent-b-dfw.xx.fbcdn.net/hphotos-prn1/v/1012733_10201076259690370_236735593_n.jpg?oh=4896ca67a34d3b223b764aba8ed308ab&oe=528A1B57 Homework Equations http://upload.wikimedia.org/wikipedia/commons/3/34/Phase-diag2.svg The Attempt at a Solution Not sure entirely...
  14. R

    Understanding Spacetime Diagrams & Relativity

    I really find difficult understanding what spacetime diagram does relativity use while defining its notion of space and time and moving observers. Can we place both a still and moving observer in the same space time diagram as in the figure (A), then the moving observer measures time going...
  15. P

    Solving Free Body Diagrams Homework

    Homework Statement http://postimg.org/image/i7phx5pp1/ Im trying to draw an FBD for this, but I don't know how the treat the distributed load or what forces the thing at E contributes. Is it some kind of support? For the distributed load, I don't know what part of it the 800N/m and...
  16. F

    Solving Free Body Diagrams with 1.9kg Object & F1=5, F2=2

    1. The question I'm struggling on has been answered on here before but with different values. Here is the link to the question https://www.physicsforums.com/showthread.php?t=344213 but on mine I have a 1.9kg object and F1=5 and F2=2. I figured out that the Y components are 0 for both of...
  17. C

    Entity relationship diagrams doubt

    I am doing a project of an entity relationship model and a doubt came: Should repeated attributes of the entities be shared? Or I must reproduce these to every entity? In another words, if two of my entities are books and magazines, shall I have a single publisher attribute, or one for each?
  18. H

    Elementary question on Moller Scattering Feynman diagrams

    Greetings, I think this will be a very quick thread. I am new to using Feynman diagrams, and have run into something that I find puzzling. The lowest-order Coulomb interaction Feynman diagram is (image from Wikipedia Moller Scattering article)...
  19. P

    Calculating & Drawing Feynman Diagrams for $\mathscr{L}$

    Homework Statement I need to calculate <\phi(x_1)\phi(x_2)\phi(x_3)> and <\phi(x_1)\phi(x_2)\phi(x_3)>_{c} and then draw Feynman diagrams when \mathscr{L} = -\left(\left(\partial_{\mu}\phi\right)^{2} + m^{2}\phi^{2}\right) - g\phi^{3} through first order in g. Homework Equations...
  20. M

    'Eyeballing' non-zero divergence and curl from vector field diagrams

    Homework Statement Explain whether the divergence and curl of each of the vector fields shown below are zero throught the entire region shown. Justify your answer.https://sphotos-a-ord.xx.fbcdn.net/hphotos-prn2/1185774_4956047513788_517908639_n.jpg Homework Equations N/AThe Attempt at a...
  21. M

    Are these motion diagrams of velocity & acceleration vectors correct?

    Homework Statement Draw motion diagrams for (a) an object moving to the right at constant speed, (b) an object moving to the right and speeding up at a constant rate, (c) an object moving to the right and slowing down at a constant rate, (d) an object moving to the left and speeding up at a...
  22. R

    How to plot correctly spacetime diagrams

    Hello, after having done a bit of exercices on Taylor & Wheeler ( just for self-study ), I felt the need to go on a bit differently, i.e. trying to solve qualitative problems instead of quantitative ones, i.e. using a bit of diagrams ( all in all, as Susskind always suggest "when you face a...
  23. Math Amateur

    MHB Exact Sequences - Diagrams that 'commute' - Example

    I am reading Dummit and Foote Section 10.5 on Exact Sequences. I am trying to understand Example 1 as given at the bottom of page 381 and continued at the top of page 382 - please see attachment for the diagram and explanantion of the example. The example, as you can no doubt see, requires...
  24. Math Amateur

    MHB Exact Sequences - Diagrams that 'commute' - vertical arrows

    I am reading Dummit and Foote on Exact Sequences and some of the 'diagrams that commute' have vertical arrows. Can someone please help me with the LaTex for these diagrams. I have given an example in the attachment "Exact Sequences - Diagrams with Vertical Arrows" - where I also frame my...
  25. tom.stoer

    List of matrix elements or Feynman diagrams

    Is there a list of matrix elements for elementary processes? ##f\bar{f}\to\gamma\to f^\prime\bar{f}^\prime## ##f\bar{f}\to Z^0\to f^\prime\bar{f}^\prime## ##ff^\prime\to W \to \ldots## ##qq^\prime\to \ldots## ##\ldots##
  26. B

    MHB Sets and Venn Diagrams for Real Numbers: Understanding Associative Axioms

    the associative axioms for the real numbers correspond to the following statements about sets: for any sets A, B, and C, we have $(A\cup B)\cup C=A\cup (B\cup C)$ and $(A\cap B)\cap C=A\cap (B\cap C)$. Illustrate each of these statements using Venn diagrams. can you show me how to draw the...
  27. J

    Penrose Diagrams - Introduction

    Penrose Diagrams -- Introduction I'm woefully ignorant of a lot of things in GR, and now that I'm moving away from my comfortable spot in condensed matter, I'd like to know how to interpret Penrose diagrams. I'm having trouble understanding what it is they're actually showing and why they'd be...
  28. R

    Shear Force and Bending Moment Diagrams

    Hello all, I'm having some difficulty understanding the relationship between the diagrams. I understand that the area under the shear force diagram curve is equal to the moment. But let's say you have a cantilever beam, 10 m long, anchored on the left. There is an evenly distributed load...
  29. A

    What is the convention for writing vector magnitudes in free body diagrams?

    Do you normally write the magnitude of the vectors in free body diagrams? I have homework on this. Is there any convention when writing the magnitude?
  30. B

    What is the relationship between equilibrium constant and phase diagrams?

    On a phase diagram, the lines are "lines of equilibrium", i.e. at any point on these lines of equilibrium there is an established equilibrium between the two phases on either side of the line. The equilibrium constant is a function of temperature and pressure, and the various other thermodynamic...
  31. H

    Calculating the net force acting on a object from diagrams

    Homework Statement Calculate the net force acting on each object indicated in the following diagrams. (diagrams attached) Homework Equations Sine Law: sin a/a = sin b/b = sin c/ c Cosine Law: c^2 = a^2 + b^2 -2ab*cos(c) SOHCAHTOA The Attempt at a Solution a) c2 = a2 + b2 –...
  32. K

    Solving Impedance Diagrams: Finding i(t) with XL = ωL

    Homework Statement Homework Equations impedence diagram, XL = ωL The Attempt at a Solution Ok i got XL = 47 ohm Then my phase angle is 88.8 degree. Then to find i(t) i have to add that angle to the function right?
  33. fluidistic

    Confused on phase diagrams for binary systems (thermodynamics)

    I'm confused regarding the phase diagrams of binary systems. Let's suppose we mix 2 liquids, A and B at a given pressure P that won't change during the whole experiment. I raise the temperature until I observe that some of the mix of liquids vaporizes. What boggles me is that it seems I can...
  34. omephy

    What are the disconnected Feynman diagrams in QFT?

    I am learning QFT from Srednicki's book. However, in Figure 9.2 Srednicki has given all connected diagrams with E=0 and V=4. Are there any way to know the disconnected diagrams? Can you tell me what they are.
  35. F

    Vector diagrams and Calculating Angles

    Homework Statement A cart of mass 357g is sent traveling down a frictionless sloped track. It's acceleration is 1.65ms-2. 1. Draw a labelled free body diagram of the cart while it is accelerating down the track. 2. Using Newton's second law, calculate the slope of the track. Homework...
  36. C

    Feynman diagrams - electrical charges

    I have a request for some explanation in Feynman diagram concerning repelling/attraction of electrical charges. I have been told that when two charges (say, e1(-) and the e2(-)) repel each other, a photon is being emitted from one of them, and the other charge is later being hit by this photon...
  37. K

    Ray diagrams for an astronomical telescope

    Homework Statement An astronomical telescope is constructed using 2 convex lenses. The objective lens is of focal length 40cm and eyepiece lens is of focal length 10cm. Let d be the distance between the 2 lenses. Draw ray diagrams for the following situations. 1.When d=50cm 2.When d>50cm...
  38. J

    Trying to understand how to read phase transformation diagrams?

    I am trying to learn how to use phase transformation diagrams and I don't get it. Any help from someone who knows about this would be greatly appreciated (I have a final tuesday) An example problem is below with the picture attached. I have to be able to find what the microstructure is after...
  39. S

    Potentials in Pourbaix Diagrams

    Hi guys, I'm having a bit of difficulty understanding Pourboix diagrams. The biggest problem at the moment is that I don't clearly understand what exactly the E° values on the y-axis are of. All the resources I've consulted haven't been especially clear about this. Sometimes they make it...
  40. K

    Drawing Relative Velocity/Triangle Diagrams?

    Homework Statement A balloon with person A in it has a force of gravity of 3000N acting on it. The balloon has an upward force of 3800N due to the hot air in it. Two people are keeping the balloon hovering just above their heads by holding onto ropes attached to each side of the balloon. If...
  41. M

    Help drawing equivalent resistor diagrams.

    Homework Statement I really just need help understanding how to re-draw a resistor diagram after calculating an equivalent resistor. Now in the picture given in the attachment, you can see that R1 and R6 are in series with each other when I compute their equivalent resistor(R1+R6), on what...
  42. J

    Are My Free Body Diagrams Correct?

    Hi to everybody Homework Statement Well I need to identify the forces acting on the bodies using free body diagramas, it´s not necessary to calculate anything, it´s only to learn about free body diagrams. I will write my thoughts about the FBD and I will appreciate a lot if you see that I´m...
  43. K

    How do you use vector scale diagrams to find total displacement?

    Just a quick question. When you are given two vectors, let's say 5m (E32N) and 6m (S23E) and we are to find the total displacement. Do you draw the first vector and then attach the second vector to do the head of the first vector? or have both vectors start a the origin.
  44. E

    Are There Multiple Resonance Structures for HCN?

    Show all possible structural diagrams for HCN. Isn't there just one? H (single bond) C (triple bond) N I can't draw a resonant structure because there is none (resonant means only moving of the bonds not the atoms, no?). I don't understand.
  45. J

    Contracting operators in Wick diagrams

    Hi, I'm currently going through Ticciati's book along with the notes from Sidney Coleman's course and I have a question pertaining to Wick diagrams/expansion of S. In their example (section 4.3 of Ticciati and lecture 9 in Coleman's notes) they never seem to contract the adjoint nucleon field...
  46. C

    Find phasor voltages, current, phasor diagrams

    Homework Statement http://imageshack.us/a/img842/2954/homeworkprobsg41.jpg a. Find the phasors for the current and the voltages of the circuit b. Construct a phasor diagram showing Vs, I, VL, Vc, and VR Homework Equations phasor current i = V/Z ic(t) = Ipeakcos2πft...
  47. K

    Understanding ray diagrams for concave lenses

    Hey guys, So some friends and I are studying for a test and we came across this question. I've absolutely no idea what the answer is simply because every website I've found only shows parallel rays and a ray going through the centre of the lens. It's incredibly aggravating. Anyway here's the...
  48. D

    Understanding Neutral Pions: Superpositions, Particles, & Feynman Diagrams

    So apparently a neutral pion is a superposition of u\bar{u} and d\bar{d}. I'm having trouble understanding what this means. I have no problem understanding how the decay products of some scattering experiment could be a superposition of these two states, but how can we treat this superposition...
  49. P

    Phasor Diagrams in single phase series circuits

    In single phase series circuits, should the current always be drawn along the x-axis and the voltage then drawn with respect to it? E.g. Should Vr be drawn in line with I, VL leading by 90 degrees (pointing upwards) and Vc lagging by 90 (Pointing down)? The reason I ask is because I've seen...
  50. P

    Shear and moment diagrams with bevel gears

    I have attached the problem. I am a bit confused on how this schematic works. The 3 forces on the bevel gear should translate to 3 moments where the bevel gear connects to the shaft. Will there also be any forces where it connects to the shaft?
Back
Top