Section Definition and 733 Threads

  1. E

    Volumes of Solids with Known Cross Section Project

    I'm trying to get started on this project but am totally confused about how to find the volume of the solid. All the information I was given was the following: y= √x boundaries: 0,9 cross sections: isosceles right triangle how the hell do I get started?!
  2. A

    Classical Limit formula for differential cross section for Hard Sphere

    I am looking for the derivation to an approximation formula for the differential cross section for hard sphere scattering in the limit of high energy. The paper that mentioned this had referred to Methods of Theoretical Physics, PM Morse and H. Feshbach page 1484 but I have no access to the...
  3. F

    A Beam of rectangular cross section 200mm deep and 100mm wide

    Homework Statement Please visit my flickr link for a scanned image of the problem statement. http://www.flickr.com/photos/93763273@N05/8815418518/lightbox/ Homework Equations M/I = σ/y = E/R This is the flexure or bending formula. The Attempt at a Solution a) = 8.333 kN...
  4. A

    Word Mac 2011 Section Break Difficulties

    Hello, I am having troubles ridding my research paper of this thorn in my side: It is a rather random line of dots. I have tried everything in my power to remove it, but to no avail. I am, for some odd reason, unable to highlight it. Furthermore, temporarily deleting the surrounding...
  5. M

    How Do You Calculate Shear Stress in Beam Sections?

    1)When we are asked to calculate the shear stress at AB should we consider the width as T or as 2T? 2)And when applying t=vq/it what sections should we take and is the value we found located on the bottom of the area?(I'm not talking about this beam but any beam in general) 3)And finally given...
  6. A

    How Does Dust Grain Size Compare to Wavelength in Scattering Light?

    Hey everyone, So I've been killing myself trying to find a good reference that talks about the wavelength dependence of dust grains when the size of the grain is about the size of the incoming light, or s~lambda. I have numerous references for when s<<lambda (absorption dominates with a...
  7. Fernando Revilla

    MHB PolkaDots 54's question at Yahoo Answers (Diagonalization, conic section))

    Here is the question: Here is a link to the question: Diagonalization to identify conic section? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.
  8. B

    The thermal activation cross section of H-3,C14

    I am doing a research on activation radionuclides resulting from thermal neutron(2200 m*s-1 or 0.0253eV) capture. The activation cross section of some nuclides(H-3,C-14,54Mn,58Co), still can't be found even many efforts were taken. The related reactions...
  9. I

    Finding the Standard Equation for the Ellipse with Given Vertices and Foci

    Homework Statement Find the equation for the conic ellipse with vertices (-2,-5) (-2, 4) and foci (-2,-4) (-2,3) Homework Equations I want to make sure I am solving the problem correctly The Attempt at a Solution (x+2)^2/8 + (y+0.5)^2/20.25 =1
  10. Q

    Partial wave scattering cross section in spherical well

    Homework Statement Consider the spherical well such that V(r<a) = -V0 and V(r≥a) = 0. Calculate the l = 0 partial wave scattering cross section in the low energy limit for this potential. Homework Equations σ = \frac{4 \pi}{k^2} * \Sigma (2l+1)*sin^2(\delta_l) The Attempt at a...
  11. C

    Octagonal Cross Section with Parabolically Increasing Span

    Octagonal Cross Section with Parabolically Increasing "Span" Hi all, could some one tell me what I am doing wrong in my analysis in the attached file? Its a parabolical flare column with an octagonal cross section. The effect of the parabolic flare simply stretches the octagon so that the...
  12. C

    Area of a tunnel with two functions creating the cross section

    Homework Statement Two curves/functions make up one side of a tunnel (the tunnel is symmetrical, so the other side is the same) Function 1: y = 5 + (2/((x-4)^3)) Function 2: y = (x -1)^3 - 5 I need to find the area of the tunnel, so I can find the amount of dirt that needs to be removed...
  13. P

    How Does Polarization Affect Electromagnetic Wave Scattering by a Free Electron?

    Homework Statement A plane monochromatic electromagnetic wave (polarized in x-direction and propagating in the z direction) is scattered by a free electron initially at rest. Homework Equations \vec{E}=E_0 \exp(i(kz-wt)) \hat{x} \vec{B}=\frac{E_0}{c} \exp(i(kz-wt)) \hat{y} The...
  14. T

    Best Way to Prep For a Perfect GRE Math Section Score

    Ok so I have a degree in math. I'm pretty sure I'll get above average on the GRE math section. But I want to get a perfect. What are the best sources to get a perfect score? I tried reading princeton review, but they mostly give me common sense type questions. Are there any books that gives me a...
  15. B

    QFT: differential cross section from center of mass to lab frame

    I have the following process: two ingoing particles, a photon hitting a nucleus, and two outgoing particles, the nucleus and a pion. I have computed |M|2 and the differential cross section in the center of mass frame dσ/dΩCM; I now have to go into the lab frame, where the nucleus is initially at...
  16. W

    Amount of scattering calculated from scattering cross section

    I was reading Wikipedia article on Rayleigh scattering and came upon this: "...the major constituent of the atmosphere, nitrogen, has a Rayleigh cross section of 5.1×10^(−31) m^2 at a wavelength of 532 nm (green light). This means that at atmospheric pressure, about a fraction 10^(−5) of...
  17. B

    Which wood cross section can carry highest uniform load

    Which wood cross sectioπ caπ carry hïghest uπiform load Homework Statement Homework Equations Moment of inertia for rectangle I=(1/12)bh3 τ=(VQ)/(I*b) σ=(MV)/I The Attempt at a Solution I started by finding reactions at B and C Then drew the sheer and moment diagrams (to save...
  18. B

    Can Someone Review My Lab's Theory Section?

    Hello, I am currently working on my lab, and am wondering if someone would be so kind as to give it a gander. The only section I need looked over is the theory section, which, incidentally, is the only part I have written thusfar. I'd really appreciate it if you could critique the theory...
  19. L

    Suface Area of a Section of a Sphere

    If a V-shaped cut were to be made through an entire sphere, radius DR (Dome Radius) with a Cutting Angle (CA- angle of the cut), what would be the surface area of the sphere section that would be cut? This is assuming that CA is less than 180 degrees. Also the Cut Depth (CD- depth of the...
  20. H

    Calculating I = 2nd Moment Of Area (m4) on C section beam

    https://skydrive.live.com/redir?resid=22F7BBABD7DEE83B!136&authkey=!AP6uQQ9mR04UuAE Can anyone please help. I have calculated the area and Neutral Axis about xx and yy of a C section beam which I know is correct (see above link) I'm have difficultly calculating the 2nd moment of area...
  21. W

    Does this code satisfy mutual exclusion, progress, and bounded waiting?

    1. Is mutual exclusion, progress, and bounded waiting satisfied in this code? Code: Two process solution to the critical section problem For this problem, you can decide any case you want whether the processes go one after the other, execute two lines at once then switch to the other...
  22. M

    Calculating Weight Savings with Rectangular Section Beam

    Here is the original question, i know the first answer as 182mm A square section cantilever beam, 3 m in length, carries a concentrated load of 10 kN at its free end. If the maximum bending stress is not to exceed 30 MPa determine the minimum dimensions of the section. Ans 182mm, What...
  23. A

    FLuid Flow through a Divergent Section

    Hi, Can Someone Elaborate the fluid(water) Characteristics Such as Velocity n pressure When it passes through a divergent Part. Actually The Fluid is pumped Out from A 0.5HP Centrifugal Pump and then made to pass through a Divergent Part.
  24. K

    What is the meaning of differential cross section in scattering theory?

    Hello! I´m confused about this concept.. It seems rather trivial, but my teacher is not that pedagogical and describes it as a rather diffcult concept so maybe I misunderstood it. Given the definition in Sakurai and the scattering of only one particle it seem to be a kind of "denisty" per...
  25. R

    Wind Tunnel Design Question Re: Test Section and Diffuser/Fan Size

    Hello, My name is Ryan and I'm a volunteer instructor with the local Royal Canadian Air Cadet squadron. I'm looking for ways to try and make the kids' aviation lessons more interactive and hands on, and so I've decided I'd like to build them a small wind tunnel, purely for flow visualization...
  26. J

    Rutherford cross section in CM frame

    Hi I need to plot the (differential) Rutherford cross section as a function of the scattering angle in the CM frame. the reaction is a typical projectile on stationary target. I know the projectile energy in the lab, θcm and the masses. I am confused over which energy to use though. I know...
  27. E

    Expression for Torsion Constant of Varying Thickness Box Section

    Hello Everyone, I am after an expression for the torsion stiffness constant of a rectangular hollow section (RHS) with varying wall thickness. I have done some research into finding an expression that allows for four varying wall thicknesses but have not found anything as of yet. The only...
  28. J

    Calculate Differential Cross Section, Amplitude from Lagrangian

    Lagrangian I have is little bit massy so I don't write in here. Like in ψψ(dagger) , or ψ∅ -> ψ∅, How can I calculate the differential cross section or total, or amplitudes?
  29. Feodalherren

    Determine the equation of the conic section

    Homework Statement Asymptotes at y=±\sqrt{10} x /5 Foci: (±\sqrt{7},0)Homework Equations The Attempt at a Solution It's obviously a hyperbola. What I can't wrap my head around is why a^2 + b^2 ≠ c^2 c = sqrt 7 ; correct? This yields 7=25+10 obviously NOT true. What am I missing here?
  30. F

    Physical meaning of Differential Cross Section in scattering

    I'm learning scattering theory from Griffiths' book, and I don't really understand the meaning of differential cross section; it's one of those things that I find hard to conceptualize and give a physical meaning to. The most intuitive description he gives is "the proportionality factor between...
  31. C

    Exploring the Topological Cross Section in Experimental Quantum Physics

    Hello, I've found in some of the articles on experimental quantum physics the term "Topological cross section" Now I'm trying to understand what is it and in particular what the difference between topological and differential cross section? Thanks in advance for suggestions on any reading...
  32. C

    How to work out the mean shear stress I section beam

    I have completed bending moment and shear force diagrams and have a question asking for the mean shear stress. I know this is worked out using the formula: tau = F/A. I am unsure of what force to use is it the max shear force on my diagram? My other thought is that it could be an avergae of...
  33. V

    Conic section problem (ellipse)

    Homework Statement Let k>0 be such that (x^2-x)+k(y^2-y)=0 defines an ellipse with focal length equal to 2 . If (p,q) are the coordinates of a point in the ellipse with q^2 - q\not=0 , then what is \frac{p-p^2}{q^2-q} ? Homework Equations The fact that the sum of the distances from...
  34. H

    Qq- ->qq- differential cross section and mandelstam variables

    qq- --->qq- differential cross section and mandelstam variables Homework Statement for the problem statement please look the attachement Homework Equations The problem is asking to express the mandelstam variables in temrs of the scattering angle θ.I would like to ask the quastion...
  35. C

    WIMP annihilation cross section

    Hi, I'm reading an article called SuperSymmetric Dark Matter, by G. Jungman et al. doi:10.1016/0370-1573(95)00058-5 and in section 3.2, he claims that <σv> ≈ \alpha^{2}(100 GeV)^{-2} \approx10^{-25} cm^{3} s^{-1},[\itex] for \alpha \approx \frac{1}{100}. When I run through the calculation...
  36. J

    Logarithms(i hope this is in the right section)

    Hey all, so i finished logarithms a few weeks ago for mathematics/precalculus 12( also known as algebra II in the states i think ) and i got 100% on the test but don't feel i understand logs very much... i understand how to solve problems and the laws completely but i started reading a book...
  37. C

    Bending moment of I section beam

    Homework Statement Hi everyone this is my first post. I am having a problem with the bending moments of the beam (see attached files). I cannot for the life of me seem to get the bending moment to finish at 0 so I can draw the bending moment diagram. I know this is generally quite a simple...
  38. Q

    What is the formula for the differential cross section and macro cross section?

    hello , can anyone give the formula of the differential cross section and the macro cross section because in each web i see a different notation thank you
  39. P

    Why is the second cross section preferred for designing a beam?

    Consider the cross section of two beams of same material as shown in the file attached. The area moment of inertia I about the central axis is equal for both the c/s. I have calculated it. Can somebody explain why the second c/s (2 in the figure ) is preferred for the design?
  40. nukeman

    Need to find sketch of Coronal section thru the posterior frontal lobe ?

    Need to find sketch of "Coronal section thru the posterior frontal lobe..." ? Hey everyone, I need to find a sketch of the following: "Coronal section through the posterior frontal lobe to reveal basal ganglis lateral to the diencephalon" ?? Having a tough time finding one. This...
  41. C

    Integral of differential cross section over solid angle

    Homework Statement Find σ , the differential cross section, starting from the expression below and integrating over solid angle Ω Homework Equations dσ/dΩ = r2sin2θ The Attempt at a Solution dσ = r2sin2θ dΩ I remember that dΩ = sinθ dθ dμ and doing the μ integral from 0...
  42. P

    Neutron capture cross section of tritium is zero

    I wish to verify a couple of assertions. From the NNDC and other references, it appears that the neutron capture cross section of 3H (Tritium) is zero to a first approximation. This holds true for all neutron energies, including cold neutrons. These statements are equivalent to asserting that 4H...
  43. T

    As we stretch a ductile material, does the x section area decrease

    ...in the elastic region? Or does the x section area decrease only after the yield point?
  44. P

    Fortran Fortran: specification statement cannot appear in the executable section

    Hi guys, I am working on a Fortran code for a while. Might seem ridiculous but to better trace it, I split code into three separate parts and trying to compile both using the command 'ifort ss.f singpot.f SNGPOT.f -o ss'. With this command I receive the error singpot.f(22): error #6236: A...
  45. F

    Spin statistic terms in absorption cross section

    'Ello, I have a question regarding the results in this paper (and another which I will mention later) http://arxiv.org/abs/hep-ph/0212199 Now, I'm not so concerned about the 'braney' bit, but more their definition of the cross section in Eqn. (46). They have included the usual (2j+1)...
  46. A

    From matrix element to hadronic cross section

    Hello, currently I work on 2->3 scattering process. So there exist five external momenta and in my case 5 different Feynman diagrams, for which I have already calculated the full matrix element. The matrix element is a function of various scalar products of the four-momenta. This scattering...
  47. N

    Volume of the solid using a cylindrical cross section

    Homework Statement Find the volume of the solid obtained by rotating the region bounded by the given curves about the specified axis. Homework Equations y = \sqrt{x-1} , y = 0, x = 5; about y = 3 The Attempt at a Solution I already completed graphing it, but not really sure how...
  48. B

    I am not sure to put this in this secton or computer section

    Can quantum computers simulate quantum effects and non quantum effects in one program? If not will they be able to in the future? Can a classical computer simulate quantum mechanics?
  49. S

    Calculate Dead Load of Beam w/ Solid Square Cross Section

    Homework Statement A beam has a solid square cross section of 100mm and is simply supported by two supports 3m apart. Calculate the dead load that can be safely supported when applied to the middle of the beam. Homework Equations Solid square cross section of beam: 100mm Material...
  50. W

    Why the photoelectric cross section decreases with the energy of the photon?

    the higher the energy of the photon, the more powerful it can ionize an atom but why then the absorption cross section decreases with the photon energy?
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