在简单的运动的题目当中，某些计算题如果按照常规方法求解，往往步骤繁多，运算复杂，过程冗长，且易出错。相反，假若遵循匀速直线运动规律，灵活地运用正反比运算技巧，就能够避繁就简、化难为易、另辟踱径、立竿见影．请看下面三例中两种解法的对比．例1南京长江大桥下层铁 Among the topics of simple movements, if some calculation problems are solved according to the conventional methods, there are many steps, complex operations, long processes, and errors. On the contrary, if we follow the law of uniform linear motion and flexibly use the pros and cons of computational techniques, we can avoid complications, make it difficult to do so, and open up new paths. Please see the comparison of the two solutions in the following three cases. Example 1 Lower Iron of Nanjing Yangtze River Bridge