考虑524)和(525) ∑ d dt ag ∑ d a dt a 上式中的两个括号正是力学系统的动能T,所以 ar d at T mi ogc dt aq aq d at aT 0 (526) dt oqa d q考虑(5.24)和(5.25) − = − = = = = = = n i i n i i n i i i n i i i i n i i m r q m r t q q r m r q r r t m q r m r 1 2 1 2 1 1 1 2 1 2 1 d d d d 上式中的两个括号正是力学系统的动能T, 所以 q T q T q t r m r i n i i − = = d d 1 0 (5.26) d d 1 = + − = s q T q T t Q