设计背景:本节内容是前面力学内容的延续,也是学习滑轮和滑轮组等知识的基础,是力学中的重要部分。在本节教学中,首先让学生从生活中的杠杆现象入手,从使用各种日常中杠杆类工具开始,进而体会分析,认识什么是杠杆,抓住杠杆的本质特征,培养学生的分析现象、主动获取知识的能力。当然力臂概念是相当抽象的,是本 Design Background: This section is the continuation of the previous mechanical content, but also to learn the basic knowledge of pulleys and pulley blocks, is an important part of mechanics. In this section of teaching, students should first start with the lever phenomenon in their daily life. Beginning with the use of various lever tools in daily life, they should understand and understand what is leverage, grasp the essential characteristics of leverage, cultivate the students’ analysis phenomenon, The ability to take the initiative to acquire knowledge. Of course, the concept of arm is quite abstract, is this