取结点A为受力平衡隔离体：.y方向的合力为零： FACy -F =0, FACy=F(↑) FACx =FACy.tan30 =0.577F(←) FAC =FACy/sin60 =F/sin60 =1.155F(↖拉力).x方向的合力为零： FAB -FACx =0, FAB =0.577F(→压力)
