Homework for Friday, Nov 13. (due in class on Friday).

[Also, be sure to work on your POW, due Wdenesday...]


61) Consider a wire loop with the shape z=r^2/a + r^4/a^3
a) Write the lagrangian for this system. (be systematic amd careful with your book-keeping).
b) Obtain the Lagrangian eqn of motion...
c) Solve for all equilibrium positions for this system. Discuss when they are stable in your opinion.
d)how does your answer for part c) depend of the spinning frequency, Omega? Are there different regimes (of Omega). What defines them? what is different about them??
e)linearize the Lag. eq of mot. around an equilibrium pt and solve for the frequency of small oscillations. PLOT your result vs Omega and discuss...


62) Consider a double pendulum with equal lengths, l, and masses, m .
a) Write the Lagrangian, (you have this already) and obtain from it the Lagrangian equations of motion .
b)Expand to lowest in order in theta1 and theta2 (for small deviations from equilibrium).
c) Can you solve for the oscillation frequencies of this system (assuming only small angle motion)? How many "normal modes" are there?? What is a normal mode (in general)? What do you think they look like for this system??