If the mass in question is a plumb bob, the horizontal component of F is important. 如果所讨论的质量是一摆锤,则重要的是F的水平分量。
Due to its huge height, its urgent time schedule and strict requirement of fine quality, its construction has been duly guided and controlled by application of the JD-91 type laser-heavy plumb bob surveying apparatus with a double controlled axial line extended technology. 由于楼层高、工期紧,为确保主体结构工程质量,垂直度控制采用激光&重锤双控轴线引伸技术,使用JD-91型建设激光测量仪。