《机械能守恒定律》是高中物理的重要内容之一,学生在学习过程中存在诸多困难。尤其是如何判断机械能是否守恒成为部分学生的学习难点。要突破难点,首先要正确理解机械能守恒定律的内容。机械能守恒定律的内容是:在只有重力或弹力做功的物体系统内,动能和势能可以相互转化,而总的机械能保持不变。定律不仅适用于物体系统,也适用于单个物体。它包含以下几层意思:(1)在只有重力做功时,物体的动能和重力势能相互转化,转化过程中机 “The law of conservation of mechanical energy” is one of the important contents of physics in senior high school. Students have many difficulties in learning process. In particular, how to determine whether the conservation of mechanical energy has become part of the learning difficulties of students. To break through the difficulties, we must first correctly understand the conservation of mechanical energy content. The law of conservation of mechanical energy states that kinetic energy and potential energy can be transformed into each other in an object system that does only work with gravity or elasticity, while the total mechanical energy remains unchanged. The law applies not only to the object system, but also to a single object. It contains the following layers of meanings: (1) When only gravity is doing work, kinetic energy and gravity potential of the object transform into each other,