A.上為左旋螺紋,下為右旋螺紋 B.上為左旋螺紋,下為左旋螺紋 C.上為右旋螺紋,下為左旋螺紋 D.上為右旋螺紋,下為右旋螺紋
A.kgf B.lbf C.N D.tf
A.600N B.980N C.1000N D.454N