物体受力情况分析是解决有关力学问题的基础和关键。在中学物理教学中,既是一个重点又是一个难点。从学生经常暴露出来的错误看,问题不少。如静置在斜面上的物块,他们认为,除受重力、支持力、静摩擦力外,还有一个下滑力作用其上。而把靠在竖直光滑墙上的梯子,施于墙的压力方向, The analysis of the force condition of the object is the basis and key to solve the mechanical problems. In middle school physics teaching, it is both a key and a difficult point. From the mistakes often exposed by students, there are many problems. Such as resting on the slope of the block, they believe that in addition to gravity, support force, static friction, there is a sliding force acting on it. And put a ladder against a vertical smooth wall and apply it to the pressure direction of the wall.