27.如右圖,F1=15kgw、F2=30kgw,AO=20cm、BO=16cm,F2=與木棒夾角為30°求合力矩=? (A)順時針60kgw-cm (B)逆時針60kgw-cm(C)順時針180kgw-cm (D)逆時針180kgw-cm