高中物理必修一第四章中,如何快捷有效地求一个物体所受合力,并据此列出动力学方程,是该章学习的一个重点、难点,新课本在牛顿第二定律应用一节,第一次引入“正交分解法”解此类习题,不仅如此,在诸如“物体平衡”等以后许多知识学习中,此方法将作为一个重要解题思路被广泛应用。本文依据教学实际,用具体事例就“正交分解法”的引入及在力的分析中使用技巧等作一些归纳和总结。 In Chapter 4 of the Physics Compulsory for Senior High School, how to find the resultant force of an object quickly and effectively and formulate the kinetic equation accordingly is one of the key points and difficulties in this chapter’s study. The New Textbook applies a new section in Newton’s Second Law , The first introduction of “orthogonal decomposition ” solution to such problems, not only that, in many knowledge learning such as “object balance ”, this method will be widely used as an important problem-solving ideas. Based on the teaching practice, this paper summarizes the introduction of “orthogonal decomposition method” and the use of skills in the analysis of force with some concrete examples.