支架平衡问题是静力学中的一类典型问题,也是静力学教学中的难点。通常讲解支架平衡问题的方法是先做一个实验,其装置见图一:在两杆的A、B端各穿有一条橡皮绳,当支架的C端不挂重物时让学生观察二杆的位置;挂上重物G后再观察,可以看到A、B处的橡皮绳都受到拉伸发生形变,A端右移,B端左移。于是教师就下一个结论:这个实验说明C端挂上重物后,AC杆受到的是拉力,沿着 Stent balance problem is a typical problem in statics, which is also a difficult point in statics teaching. Usually explain the issue of stent balance is to do an experiment, the device shown in Figure 1: A, B in both ends of the rod is worn with a rubber cord, when the stent does not hang the C-side heavy objects allow students to observe two shots Position; hanging heavy object G and then observe, you can see the A, B at the rubber band are subject to tensile deformation, A side to the right, B side left. So the teacher to the next conclusion: This experiment shows that C-hung heavy objects, AC rod is subjected to tension, along