2质点系的绝对运动对动质心的动量矩 ri=ctr v =卩+ C L=∑La=r X Lo=∑r1×mv;=∑(c4r×m ∑r×mv1+∑r×m1v re×P+Lc 55 2.质点系的绝对运动对动质心的动量矩 O x y z c x y z ri rc r i Mi Lc =Lci = r i mivi ri = rc + r i vi = vc + vri LO =  ri  mivi =  (rc + r i )  mivi =  rc  mivi + r i  mivi = rc  P + Lc