“势能的改变”是下节“能量守恒定律”的知识基础,是本章的一个重要知识点。本节进述重力势能及其相对性,重力势能的变化以及与重力做功的关系。由于与动能定理的表述不一致,学生往往不易理解,教学时最好能结合一些实例,从功能关系、能量转化的角度分析,解开学生的困惑,为下节讲机械能守恒定律做好准备。 “The change of potential energy ” is the knowledge base of the next section “Law of Conservation of Energy ”, which is an important point in this chapter. This section reviews the potential and relativity of gravitational forces, the changes in gravitational potential energy, and the relationship with gravitational work. Due to the inconsistency with the expression of kinetic energy theorem, students are often not easy to understand. In teaching, it is best to combine some examples to analyze the functional relationship and energy conversion, to solve the confusion of students and prepare for the conservation law of mechanical energy in the next section.