d M(mv=M(F d Mo(mv)=Mo(F) M,(m)=M,(F) d dr M(mv)=M(F) 2.质点的动量矩守恒定律 1若∑M0(F)=0M(m)=恒矢量 2.若M(F)=0M2(m)=恒量M ( v) M (F) O m O dt d =          = = = ( ) ( ) ( ) ( ) ( ) ( ) v F v F v F z z y y x x M m M dt d M m M dt d M m M dt d 2. 质点的动量矩守恒定律 .  (F) = 0 若 Mz 2 MO (mv) =恒矢量 Mz (mv) =恒 量 .  M (F) = 0 若 O 1