Section Definition and 733 Threads

  1. B

    Having some issues deriving internal force functions for a section.

    Homework Statement I have a 13 foot long beam supported by a pin at x = 0 feet and a roller at x = 9 feet. There is a triangular distributed load of 50 lb/ft from 0 ft to 9 ft. (Increasing as it approaches 9 ft) At the end of the beam there is a moment of 200 lb-ft counter-clockwise.Homework...
  2. Safinaz

    2 -> 2 hadronic production cross section

    Hi all, Could anyone help for calculating the hadronc production cross section for example for tree level : p p > t t~ process, I try to calculate, but the first problem I meet is a negative value of the matrix element amplitude (and so cross section ) and a negative ## \hat{t} ## Mandelstam...
  3. E

    Question regarding Lab cross section of spectra

    I'm currently doing some research at the moment for my professor, and he gave me a list of things to look at. Before he had me calculate the "real center of mass cross section." Now, starting at point 0 for publication, he's having me go through and do some other things. In his list of things to...
  4. Math Amateur

    MHB Algebraic Geometry - D&F Section 15.1, Exercise 19

    Exercise 19 of Section 15.1 in Dummit and Foote reads as follows: ------------------------------------------------------------------------------ 19. For each non-constant f \in k[x] describe \mathcal{Z}(f) \subseteq \mathbb{A}^1 in terms of the unique factorization of f in k[x] , and...
  5. F

    Interpretation of Cross Section of p,n reaction mb or mb/MeV

    Dear Forum : I'm reading a cross section data of 20MeV proton + 16O reaction from ICRU 63. ( as attachment and link http://ppt.cc/qf-9 ) The total cross setion of (p,n) reaction is 4.372mb However, the cross section of emitting neutron of energy between 0 to 1.5MeV is 0.91 mb / MeV. The...
  6. Math Amateur

    MHB Quotient Groups - Dummit and Foote, Section 3.1, Exercise 17

    I am reading Dummit and Foote Section 3.1: Quotient Groups and Homomorphisms. Exercise 17 in Section 3.1 (page 87) reads as follows: ------------------------------------------------------------------------------------------------------------- Let G be the dihedral group od order 16. G = <...
  7. Math Amateur

    Primary Ideals, prime ideals and maximal ideals - D&F Section 15.2

    I am studying Dummit and Foote Section 15.2. I am trying to understand the proof of Proposition 19 Part (5) on page 682 (see attachment) Proposition 19 Part (5) reads as follows...
  8. Math Amateur

    MHB Primary Ideals, prime ideals and maximal ideals - D&F Section 15.2

    I am studying Dummit and Foote Section 15.2. I am trying to understand the proof of Proposition 19 Part (5) on page 682 (see attachment) Proposition 19 Part (5) reads as follows...
  9. Math Amateur

    Algebraic Geometry - D&F Section 15.1, Exercise 24

    Dummit and Foote Section 15.1, Exercise 24 reads as follows: --------------------------------------------------------------------------------------------------------- Let V = \mathcal{Z} (xy - z) \subseteq \mathbb{A}^3 . Prove that V is isomorphic to \mathbb{A}^2 and provide an explicit...
  10. Math Amateur

    MHB Algebraic Geometry - D&F Section 15.1, Exercise 24

    Dummit and Foote Section 15.1, Exercise 24 reads as follows: --------------------------------------------------------------------------------------------------------- Let V = \mathcal{Z} (xy - z) \subseteq \mathbb{A}^3 . Prove that V is isomorphic to \mathbb{A}^2 and provide an explicit...
  11. Math Amateur

    Elementary Algebraic Geometry - D&F Section 15.1 - Exercise 15

    Dummit and Foote (D&F), Ch15, Section 15.1, Exercise 15 reads as follows: ---------------------------------------------------------------------------------------------------- If k = \mathbb{F}_2 and V = \{ (0,0), (1,1) \} \subset \mathbb{A}^2 , show that \mathcal{I} (V) is the...
  12. Math Amateur

    MHB Elementary Algebraic Geometry - D&F Section 15.1 - Exercise 15

    Dummit and Foote (D&F), Ch15, Section 15.1, Exercise 15 reads as follows: ---------------------------------------------------------------------------------------------------- If k = \mathbb{F}_2 and V = \{ (0,0), (1,1) \} \subset \mathbb{A}^2 , show that \mathcal{I} (V) is the...
  13. Math Amateur

    Affine Algebraic Sets - D&F Chapter 15, Section 15.1 - Example 2

    I am reading Dummit and Foote Ch 15, Commutative Rings and Algebraic Geometry. In Section 15.1 Noetherian Rings and Affine Algebraic Sets, Example 2 on page 660 reads as follows: (see attachment) ----------------------------------------------------------------------------------------------...
  14. Math Amateur

    Affine Algebraic Sets - D&F Chapter 15, Section 15.1 - Example 3 - pag

    I am reading Dummit and Foote Ch 15, Commutative Rings and Algebraic Geometry. In Section 15.1 Noetherian Rings and Affine Algebraic Sets, Example 3 on page 660 reads as follows: (see attachment) ----------------------------------------------------------------------------------------------...
  15. Math Amateur

    MHB Affine Algebraic Sets - D&F Chapter 15, Section 15.1 - Properties of the map I

    I am reading Dummit and Foote Ch 15, Commutative Rings and Algebraic Geometry. In Section 15.1 Noetherian Rings and Affine Algebraic Sets, the set \mathcal{I} (A) is defined in the following text on page 660: (see attachment)...
  16. Math Amateur

    MHB Affine Algebraic Sets - D&F Chapter 15, Section 15.1 - Example 3 - page 660

    I am reading Dummit and Foote Ch 15, Commutative Rings and Algebraic Geometry. In Section 15.1 Noetherian Rings and Affine Algebraic Sets, Example 3 on page 660 reads as follows: (see attachment)...
  17. Math Amateur

    MHB Affine Algebraic Sets - D&F Chapter 15, Section 15.1

    I am reading Dummit and Foote Ch 15, Commutative Rings and Algebraic Geometry. In Section 15.1 Noetherian Rings and Affine Algebraic Sets, Example 2 on page 660 reads as follows: (see attachment)...
  18. C

    Length on vibrating section of violin

    Homework Statement A particularly beautiful note reaching your ear from a rare Stradivarius violin has a wavelength of 39.1 cm. The room is slightly warm, so the speed of sound is 344 m/s. If the string's linear density is 0.560g/m and the tension is 160N , how long is the vibrating section...
  19. Math Amateur

    MHB Field Theory - Nicholson - Splitting Fields - Section 6.3 - Example 1

    I am reading Nicholson: Introduction to Abstract Algebra, Section 6.3 Splitting Fields. Example 1 reads as follows: (see attachment) -------------------------------------------------------------------------------------------------- Example 1. Find an extension E \supseteq \mathbb{Z}_2 in...
  20. Math Amateur

    MHB Field Theory - Nicholson - Algebraic Extensions - Section 6.2 - Example 15

    I am reading Nicholson: Introduction to Abstract Algebra, Section 6.2 - Algebraic Extensions. Example 15 on page 282 (see attachment) reads as follows: --------------------------------------------------------------------------------------------------------------------------------- Example 15...
  21. Math Amateur

    MHB Field Theory - Nicholson - Algebraic Extensions - Section 6.2 - Example 13

    xample 13 from Nicholson: Introduction to Abstract Algebra, Section 6.2, page 282 reads as follows: (see attachment) ------------------------------------------------------------------------------------------------------------------ Example 13: If u = \sqrt[3]{2} show that \mathbb{Q}(u) =...
  22. Math Amateur

    MHB Field Theory: Nicholson, 6.2 Algebraic Extensions - Example 14 (p. 282) Solution

    I am reading Nicholson: Introduction to Abstract Algebra, Section 6.2 Algebraic Extensions. Example 14 on page 282 (see attachment) reads as follows: ------------------------------------------------------------------------------------------- Example 14. Let E \supseteq F be fields and let...
  23. A

    Pi (π) section symmetrical attenuators

    Homework Statement (a) Design a π section symmetrical attenuator to provide a voltage attenuation of 15 dB and a characteristic impedance of 600 Ω. (b) Construct and test the π section attenuator. Measure and record the input & output voltages of the attenuator and determine the...
  24. Math Amateur

    MHB Field Theory: Nicholson Alg Ext, Sec 6.2 Ex 13 Pg 282 Explained

    I am reading Nicholson: Introduction to Abstract Algebra, Section 6.2 Algebraic Extensions. Example 13 on page 282 (see attachment) reads as follows: "If u = \sqrt[3]{2} show that \mathbb{Q}(u) = \mathbb{Q}(u^2) " In the third line of the explanation - see page 282 of attachment - we...
  25. Math Amateur

    MHB Field Theory - Nicholson - Algebraic Extensions - Section 6.2 - pages 281-282

    I am reading Nicholson: Introduction to Abstract Algebra Section 6.2 Algebraic Extensions. On page 282 the Corollary to Theorem 5 states the following: (see attachment for Theorem 5 and the Corollary)...
  26. Math Amateur

    MHB Field Theory - Nicholson - Section 6.2 - Exercise 31

    In Section 6.2 of Nicholson: Introduction to Abstract Algebra, Exercise 31 reads as follows: Let E \supseteq F be fields and let u \in E be transcendental over F. (a) Show that F(u) = \{ f(u){g(u)}^{-1} \ | \ f,g \in F[x] ; g(x) \ne 0 \} (b) Show that F(u) \cong F(x) where F(x) is the...
  27. D

    How Does Resistivity Vary in a Conical Material with Changing Dimensions?

    Homework Statement A piece of conically-shaped material is placed in a circuit along the x-axis. The resistivity of this material varies as rho=(6*10^6)*x^4 (where x is measured in meters and rho is measured in ohm*meters), and its radius varies linearly as a function of x, ranging from...
  28. B

    How Does Taylor's Mechanics Address Rocket Momentum with Changing Mass?

    Hello, I am reading section 3.2, concerning the analyzation of a moving rocket with a changing mass. (I couldn't find a preview of the book in google books, so hopefully someone out there has this textbook.) Here is an except from the book, but be warned that I am adding notes in brackets...
  29. M

    Determining internal force with section cut on structure

    Homework Statement Homework Equations The Attempt at a Solution Hello, my problem seems to be that I have two values that are possible for the Force FG, but I also am not considering the internal forces F_DE and F_FE. I'm not sure how to go about finding those if they are important for...
  30. Math Amateur

    MHB Field Theory - Basic Theory - D&F Section 13.1

    I am reading Dummit and Foote (D&F) Section 13.1 Basic Theory of Field Extensions. I have a question regarding the nature of extension fields. Theorem 4 (D&F Section 13.1, page 513) states the following (see attachment)...
  31. Math Amateur

    MHB Field Theory - Algebraic Extensions - D&F - Section 13.2 - Exercise 7, page 530

    ------------------------------------------------------------------------------------------------ 7. Prove that \mathbb{Q} ( \sqrt{2} + \sqrt{3} ) = \mathbb{Q} ( \sqrt{2} , \sqrt{3} ). Conclude that [\mathbb{Q} ( \sqrt{2} + \sqrt{3} ) \ : \ \mathbb{Q} ] = 4 . Find an irreducible...
  32. Math Amateur

    MHB Field Theory - Algebrais Extensions - D&F - Section 13.2 - Exercise 4, page 530

    Can someone help me get started on the following problem. Determine the degree over \mathbb{Q} of \ 2 + \sqrt{3} and of 1 + \sqrt[3]{2} + \sqrt[3]{2} Peter [This has also been posted on MHF]
  33. Math Amateur

    MHB Field Theory - Algebrais Extensions - D&F - Section 13.2 - Exercise 2, page 529

    Dummit and Foote Exercise 2, Section 13.2, page 529 reads as follows: ------------------------------------------------------------------------------------------------------------------ 2. Let g(x) = x^2 + x -1 and let h(x) = x^3 - x + 1 . Obtain fields of 4, 8, 9 and 27 elements by...
  34. M

    Finding the slope of a section of a graph in excel

    Hello, I have a graph of a tensile test of a metal sample, and I wish to find the slope on the graph of only the elastic region of the graph, meaning of the entire graph, there is only one section of it that I am interested in finding the slope for. Is there a way in excel to make it such...
  35. Math Amateur

    MHB Algebraic Extensions: Dummit & Foote Section 13.2, Example 2 pg 526 - Help!

    I am reading Dummit and Foote on algebraic extensions. I am having some issues understanding Example 2 on page 526 - see attachment. Example 2 on page 526 reads as follows...
  36. Math Amateur

    MHB Field Theory - Algebrais Extensions - Dummit and Foote Section 13.2

    I am trying to clarify my understanding of Proposition 11 of Dummit and Foote Ch13 Field Theory concerning the degree of \alpha over F. Proposition 11 reads as follows...
  37. E

    Steel Angle Plastic Section Modulus

    Hi all, I am after trying to find the plastic section modulus about both local axes (x & y) after having calculated them for the global axes (n & p). Is there a way I can transform global to local using Morh’s circle to evaluate plastic section properties? Attached is the key diagram I am...
  38. A

    Torsion of rectangular cross section rotated at an angle?

    I want to use a rectangular cross section to act as a torsion spring that can be adjusted. The idea is that the adjustment would be made via rotating the rectangular cross section about it's center at an angle theta. I've used parallel axis theorem before, but I don't think that is applicable...
  39. K

    Understanding a rudimentary solution to Critical Section Problem

    (Source: page 20 of this :http://www.ics.uci.edu/~bic/courses/JaverOS/ch2.pdf) The part I put in bold looks like nonsense. Since program1 executes after the Critical Section and after turn gets set to 2, there is nothing stopping p2 from leaving its wait loop and entering its critical...
  40. Math Amateur

    MHB Generalised Quaternion Algebra over K - Dauns Section 1-5 no 19

    In Dauns book "Modules and Rings", Exercise 19 in Section 1-5 reads as follows: (see attachment) Let K be any ring with 1∈K whose center is a field and 0 \ne x, 0 \ne y \in center K are any elements. Let I, J, and IJ be symbols not in K. Form the set K[I, J] = K + KI + KJ + KIJ of all K...
  41. Math Amateur

    MHB Generalised Quaternion Algebra over K - Dauns Section 1-5 no 18

    In Dauns book "Modules and Rings", Exercise 18 in Section 1-5 reads as follows: (see attachment) Let K be any ring with 1∈K whose center is a field and 0 \ne x, 0 \ne y \in center K are any elements. Let I, J, and IJ be symbols not in K. Form the set K[I, J] = K + KI + KJ + KIJ of all K...
  42. J

    Matrix maybe it can go in precalc section ?

    Homework Statement Let A and B be matrices of the same size. a.) prove the jth column of ## A + B## is ## a_j + b_j ## Homework Equations Where is i? In their question? The Attempt at a Solution What if you did this. ## A= \begin{pmatrix} a_{1j}\\ a_{2j}\\ a_{3j}...
  43. Math Amateur

    MHB Generalised Quaternion Algebra over K - Dauns Section 1-5 no 17

    In Dauns book "Modules and Rings", Exercise 17 in Section 1-5 reads as follows: (see attachment) Let K be any ring with 1 \in K whose center is a field and 0 \ne x, 0 \ne y \in center K any elements. Let I, J, and IJ be symbols not in K. Form the set K[I, J] = K + KI + KJ + KIJ of all K...
  44. S

    Positron cross section with H,D,T

    I have a question about cross section probability for a positron (e+) to interact with the electron (e-) that would be bound to three different atomic systems (1) hydrogen atom: H(e-), (2) deuterium atom: D(e-), (3) tritium atom: T(e-). My hypothesis is that a positron (e+) would have the...
  45. K

    Calculation of neutron transport cross section

    I have a book on nuclear reactions which details the mean free paths for thermal neutron scattering as: 0.37cm for water and 2.2cm for heavy water The transport cross sections are listed as 0.45cm for water and 2.6cm for heavy water. Does anyone know how to calculate these from the thermal...
  46. L

    E+e- -> gamma f0 -> gamma pi0 pi0 cross section with VMD

    e+e- --> gamma f0 --> gamma pi0 pi0 cross section with VMD Homework Statement Find the cross-section of ##e^+e^- \to \gamma f_0(980) \to \gamma \pi^0 \pi^0## using the vector meson dominance model. Homework Equations Some Feynman's rules: The photon propagator is -i...
  47. D

    Why does the cross section drop between resonances?

    Hello. When you have a plot of the cross section in function of the centre of mass energy of an e+e- -> hadrons collision, you get a graph with a few peaks which are due to the resonances (ρ, ω, J/ψ...). But I don't understand why at a resonance, the cross section goes up? Or other way...
  48. R

    What will be the cross section area of rod?

    If a metal rod of 20 cm is charged with 10 μC, then what should be its cross section area so as to prevent electric discharge (electric breakdown) ?
  49. B

    MHB Problem 15 section 5.1 from Bartle

    hello. This is my first post. Of course I read rules, but I may make mistakes about posting. If I have a mistake about something, please tell me. Now, this problem15 is in section 5.1 from Bartle. f: (0,1)→R be bounded but such that x→0,lim f does not exist. Show that there are two sequences...
  50. S

    Difference in thermal n cross section for Be-9 and B-10

    I have a question. From this government reference: http://www.ncnr.nist.gov/resources/n-lengths/ the thermal neutron cross section for stable isotope Be-9 = 0.0076 barns. This means Be-9 is not expected to absorb a thermal neutron, the probability of this is very, very low. The Be-9...
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