Dynamic from the general equation of dynamics we have (OA-QB + OB COS a)o,+(CB coS a+Osin a-LBOSB=0 The system has two degree of freedom, we can choose &x, and s as independent virtual displacement. Moreover Q=mg. So we get Ma +ma-ma. cosa=0 macosa+mgsina-ma =0 lB B Solving them we get oxa SB m sin 2a a P 2(M+msin a g11 From the general equation of dynamics we have (− − + cos ) + ( cos + sin − ) = 0. B r B e A B r B e A B Q Q Q  x Q  Q  Q s The system has two degree of freedom, we can choose as independent virtual displacement. Moreover, . So we get A B x and s Q=mg cos sin 0 cos 0 + − = + − = r r ma mg ma Ma ma ma    Solving them we get . 2( sin ) sin 2 2 g M m m a   + =