(4)平面运动刚体上力系的功 r ow Fd +E· d drc= F cos bcMdp dh OW=LOW=2F.drc+2Mc(E)do Fr.dr tM.de 12 Fn·dra+ R Mrd（4）平面运动刚体上力系的功 Mi C Fi drC driC d d i d C d ic r = r + r i C i i C i i d d W d F r F r F r =  +   =     M d d F CM d C i i i C i i ( ) cos F F r =  =     d M d W W d M d R C C i i C C i =   + =  =   +  F r F r (F )    W d MC d C C  R C  =   + 2 1 2 1 1 2 F r