当刚刚讲完“机械能”一节，在讨论课后练习题“人们骑自行车上坡前，为什么往往要先加紧蹬几下后再爬坡感觉容易些”时，大部分学生会不加思索的回答：“因为惯性．”当教师再问：“我们骑自行车下坡时，不需要蹬车，车速却越来越快，也是因为惯性吗？”这时学生才与“机... When the “Mechanical Energy” section was just finished, most students would answer without thought after discussing the after-school exercise “Why people tend to step up and make a few more trips before climbing uphill.” : “Because of inertia.” When the teacher asked: “When we ride a bicycle downhill, we don’t need to ride a car, but the speed is getting faster and faster, but also because of the inertia?” At this time students and the "machine ...