学 ∑(F-m2a)Gr=0 (10-3-1) 得:∑F·-∑mao=0 (c) 第一项:主动力在质点系的虚位移的元功之和: ∑F·=∑Q,c 第二项:惯性力在质点系的虚位移的元功之和: k dr ∑ma,C=∑ma1(∑x·c,) aq k ar =2∑ma1·c1= 0 (e) =1 1414 ( ) 0 (10 3 1) 1 − = − − = n i i i i i F m a r ( ) 1 1 F r Q q d k j j j n i i i = = = = = − = n i n i i i i i i F r m a r c 1 1 得: 0 ( ) 第一项:主动力在质点系的虚位移的元功之和: 第二项:惯性力在质点系的虚位移的元功之和: 0 ( ) ( ) 1 1 1 1 1 q e q r m a q q r m a r m a j j i k j n i i i n i j k j j i i i n i i i i = = = = = = = =