Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Classical Dynamics of Particles & Systems

  1. Jul 18, 2013 #1
    This is an image of Classical Dynamics of Particles & Systems, chapter 1

    In deriving the equations for the rotation of a coordinate system


    I understand the equations 1.2a & 1.2b b, but why is the projection of x2 on the x'1 equal to ab +bc

    and why is the vector de equal to the vector Of?

    I tried the whole afternoon drawing triangles, writing vectors as one another, cosinus,sinus rules, congruent triangles everything I could think off, yet I can't prove it.
    It seems obvious, but I want proof :D

    (how to resize my image)

    (btw, this is self-study, no homework or anything like that)
  2. jcsd
  3. Jul 18, 2013 #2
    What does the asterisk in the problem statement indicate?
  4. Jul 19, 2013 #3

    Stephen Tashi

    User Avatar
    Science Advisor

    I don't know the answers to your questions. It's worth reading the errata for the book, even if it isn't relevant to this particular problem: http://astro.physics.sc.edu/Goldstein/
  5. Aug 2, 2013 #4
    It's not Goldstein. But from Marion Jerry, but ok, will check errata.

    Just saying that x1,x2,x3 are equivalent to x,y,z in the Cartesian plane.
  6. Aug 2, 2013 #5

    Stephen Tashi

    User Avatar
    Science Advisor

  7. Aug 3, 2013 #6
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Classical Dynamics of Particles & Systems
  1. Funky Particle System (Replies: 0)

  2. Dynamic Optimization (Replies: 1)