效率的概念已经广泛应用于工作、生活和学习等方面,可以说机械效率与我们的生活息息相关.简单机械的机械效率是力学中的重点和难点,也是中考题中几乎必考的一个知识点,学生平时做的练习很多,为什么有很多学生仍然一知半解,原因之一是没有理解和理清几种简单机械之间的关系,所以解题时效率就低. The concept of efficiency has been widely used in work, life, and learning. It can be said that mechanical efficiency is closely related to our lives. The mechanical efficiency of simple machinery is the key and difficult point in mechanics, and it is also a knowledge point that is almost mandatory in the examination questions. The students usually do a lot of exercises, and why one of the reasons why many students still lack understanding is that they do not understand and clarify the relationship between several simple machines, so the efficiency of solving problems is low.