棒面接触时弹力方向的演示浙江省慈溪锦堂师范学校何定英棒跟面接触时，弹力方向的判断是教学中的难点之一．下面两例中，学生的错误具有典型意义．例１如图１所示，棒ＡＢ的Ａ端着地，Ｂ端靠在光滑的竖直墙壁上，问棒对墙的弹力方向应是Ｆ１和Ｆ２中的哪一个？图１图２例... Demonstration of the direction of elasticity when the sticks are in contact With He Dingying, Cixi Jintang Normal School, Zhejiang Province, when he comes into contact with the surface, the determination of the direction of elasticity is one of the difficulties in teaching. In the following two cases, the student’s mistake has typical significance. Example 1 As shown in Fig. 1, the rod AB is grounded on the A end and the B end on a smooth vertical wall. Which one of F1 and F2 should be the spring direction of the rod against the wall? Figure 1 Figure 2 Case...