机械效率问题既可以考察功和机械效率的概念及计算,又可以综合考察功率、力的平衡、力和运动、简单机械的有关概念及计算等.题目综合性强,考察知识点多,难度大.但只要我们抓住了这类题的特点和一般方法,问题就能得到正确而迅速地解答.解答这类题的一般方法是,在正确判定有用功和总功的基础上,从入手分析(不管是否求),再综合运用 The problem of mechanical efficiency can not only investigate the concept and calculation of work and mechanical efficiency, but also comprehensively examine power, force balance, force and motion, related concepts and calculations of simple machinery, etc. The topic is comprehensive, and there are many knowledge points and difficulties. However, as long as we grasp the characteristics and general methods of such questions, the questions can be answered correctly and promptly. The general method for solving such questions is to start from the analysis based on the correct determination of useful work and total work. (regardless of whether or not seeking)