编者：本文侧重论述的《机械能》、《分子运动论》、《内能》、钢能的利用》，是物理学中重要内容之一．能的转化和守恒定律是自然界普遍适用的基本规律，利用它，人类得以更深入地认识自然，学会用能量观点解释现象、思考问题和解决问题，这对学好物理和掌握科学方法是十分有 Editor: This article focuses on the “mechanical energy”, “Molecular Movement Theory”, “Internal Energy”, the use of steel energy", is one of the important contents of physics. The law of conversion and conservation of energy is a basic law that is universally applicable in nature. Using it, human beings can gain a deeper understanding of nature, learn to use energy viewpoints to explain phenomena, think about problems, and solve problems. This is very helpful for learning physics and mastering scientific methods.