Recent content by beowulf.geata

  1. beowulf.geata

    Reversing transformations of displacements

    Thanks very much! I now see the error of my ways :-)
  2. beowulf.geata

    Reversing transformations of displacements

    Homework Statement I've just started (self-studying) Neuenschwander's Tensor Calculus for Physics and I got stuck at page 23, where he deals with transformations of displacements. I've made a summary of page 23 in the first part of the attached file. Homework Equations I want to use the...
  3. beowulf.geata

    Current density and skin depth

    Homework Statement A thin metallic strip on a circuit board has length L, width a and thickness t, with L>>a>> t. Derive an expression for the resistance between the ends of the strip at frequency f, assuming that the skin depth is small compared with the thickness t. Homework Equations The...
  4. beowulf.geata

    Quinn and Ittner's (1963) superconductivity experiment

    Many thanks. That was very helpful. I can see now that I was confused by the fact that the figure is not drawn to scale. (Just for the sake of completeness: I made a mistake with the date of the experiment, which dates back to 1962, not 1963!)
  5. beowulf.geata

    Quinn and Ittner's (1963) superconductivity experiment

    Homework Statement The problem is Exercise 1 here: http://www.open.edu/openlearn/science-maths-technology/engineering-and-technology/engineering/superconductivity/content-section-2.1. I am interested in question (c), where you are asked to estimate the maximum possible resistivity...
  6. beowulf.geata

    Bead attached to a spring and moving along a horizontal wire

    The integral should evaluate to kx2/2 - kl0(h2 + x2)1/2 + C. Hence, the difference between my solution and the book's is: kx2/2 - kl0(h2 + x2)1/2 + C - (k(h2 + x2)1/2l0 + (1/2)kh2 + (1/2)kx2 - (1/2)kl02) = C - (1/2)kh2 + (1/2)kl02, so the two solutions do appear to differ by a...
  7. beowulf.geata

    Bead attached to a spring and moving along a horizontal wire

    I'm self-studying an introductory book on mathematical methods and models and came across the following problem: 1. A bead of mass m is threaded onto a frictionless horizontal wire. The bead is attached to a model spring of stiffness k and natural length l0, whose other end is fixed to a...
  8. beowulf.geata

    Tug-of-War Paradox: Forces & Balance in Red/Blue Contest

    Homework Statement Imagine a tug-of-war contest between red and blue teams. (a) Early on in the proceedings, the two teams are equally matched and so there is no movement of the rope at all. (b) Having been more moderate over lunch, the blue team begins to pull the red team along at an...
  9. beowulf.geata

    Calculating Area of Hemisphere Cut by Cylinder

    I've just realized that there is a mistake in my limits of integration for z. Apart from 0, the other limit is sqrt(4 - (x^2 + y^2)), not sqrt(4 - x^2), and, since this z also belongs to the cylinder, z = sqrt(4 - 2x) and this leads to the correct result, i.e. 4.
  10. beowulf.geata

    Calculating Area of Hemisphere Cut by Cylinder

    Homework Statement Find the area of the portion of the cylinder x^2 + y^2 = 2x that lies inside the hemisphere x^2 + y^2 + z^2 = 4, z \geq 0. Hint: Project onto the xz-plane. Homework Equations I want to use the formula for surface area \int\int\frac{|\nabla f|}{|\nabla...
  11. beowulf.geata

    Changing order of integration in spherical coordinates

    Homework Statement Let D be the region bounded below by the plane z=0, above by the sphere x^2+y^2+z^2=4, and on the sides by the cylinder x^2+y^2=1. Set up the triple integral in spherical coordinates that gives the volume of D using the order of integration dφdρdθ.Homework Equations The...
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