"Geometrical methods in classical mechanics"
Prof. David Khmelnitskii
of Physics, Cambridge University
This is a talk not about any original contribution but
rather of a pedagogic nature. I begin with the notion
of a variational principle, as a substitution for an
equation of motion, and with geometrical interpretation
of this principle. The end of the story brings a simple
answer to the question why the orbits of planets and
comets around Sun are closed lines.
Dr. Ron Lifshitz, x5145