当某一个物理量存在极值时,其导数为零。用求导的方法解物理极值问题,对学生的要求并不太高,但作为传道、授业、解惑的教师,如果不能居高临下,就无法透彻的分析问题。现举几例加以说明:题1:如图1所示,用轻绳系一小球,由水平静止释放,在向最低点运动的过程中,重力对小球做功的功率 When there is an extreme value of a physical quantity, its derivative is zero. Solving physics extremes by the method of seeking guidance does not require too much from the students. But as a preacher, a professor, and a teacher who confuses questions, you can not thoroughly analyze the problem if you can not command condescension. Here are a few examples to illustrate: Question 1: As shown in Figure 1, a ball with a light rope, released by the level of static movement in the lowest point, the power of gravity on the ball doing work