But obviously we have entirely different tastes in light reading. ;-)
Bill Bartlett Bracknell Tas
At 7:22 AM -0700 13/8/08, Chuck Grimes wrote:
>``Have you been on the sauce again? "Lagrangian or Hamiltonian
>formulation"???'' Bill Bartlett
>
>Yes, I have just started. I got home from work a few minutes ago, and
>poured a stiff martinis to consider Les and John's great
>answers. Thanks to both of you. It is difficult to get good answers
>from very vague and confused questions, and I appreciate the effort.
>
>While this is probably gobbly-gok to most LBO, I'll explain my
>interest in this stuff. First what is this shit about? It is about how
>to look at physical problems. You can look at them as problems of points
>and their changing positions, or you can look at them as energy and time.
>In a really great little book, two Russians, Lev Landau and Evgeny
>Lifshitz, open their lectures by recasting classical Newtonian
>mechanics of a point and its motions by introducing:
>
>``The most general formulation of the law governing the motion of
>mechanical systems [that] is the _principle of least action_ or
>_Hamilton's principle_, according to which every mechanical system is
>characterized by a definite function ... or briefly L(q, dot-q, t)....
>
>Let the system occupy, at the instants t_1 and t_2, positions defined
>by two sets of values of the coordinates q^(1) and q^(2). The
>condition in the system moves between these positions in such a way
>that the integral
>
> S = t_2 INT t_1 L(q, dot-q, t) dt, (2.1)
>
>takes the least possble value. The function is called the Lagrangian
>of the system concerned, and the integral (2.1) is called the
>action.... '' (4p, Landau LD, Lifshitz EM, Mechanics and
>Electrodynamics, Pergamon Press: 1972.)
>
>Here the coordinates are q_i, and the velocities are dot-q_i.
>I thought Les's comment on the religious features of the Lagrangian
>was hilarious.
>
>I will meditate on these posts. Thanks again to you both.
>
>CG
>
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