Homework Notes:

• Homework Set 7:
  • Some notes on the differentiation of E and B (electromagnetic wave vectors)
  • Section 3.10 # 12: There is a typo - the problem was intended to read
    F(r,phi,theta) = e_r + r e_phi  + r cos(theta) e_theta ;
    that is, if one compares the answer at the back of the book, the original intention of the authors was to have cos(theta) instead of cos(phi) . However, it doesn't matter which of these you choose (as long as your calculation is correct...)
  • In equation (5.102) on p.317, the first x' (in the transformation equation for the old coordinate x in terms of the new (x', y', z')) should not be boldface (a vector x' makes no sense in this context).
  • New: Problem 8 in Section 5.8 is longer than I thought; please do not spend too much time on this, especially on part (b). Part (a) is best done using tensor notation, rather than writing out all components, and is not too bad, but part (b) (invariance of curl under orthogonal transformations) is quite tricky, and I will post a solution on Friday.
    .
• Homework Set 9:
  • Correction: there is a sign error in the equation in part (d) of the extra problems: the work done by the force is
    W = -GMm(1/R₀ - 1/R₁)