在研究运动的合成与分解时,有一道常见的传统题目:划速为 v_划的小船在水速为 v_水的小河中横渡此河。问船应向哪个方向划行,渡河的航线最短?此题在参考书中常能见到,一般的分析过程是这样的:如图1所示,要想船渡河的航线最短,船必须在垂直河岸的方向上过河, When studying the synthesis and decomposition of sports, there is a common traditional problem: a boat with a speed of v_ is crossing a river in a river with a water speed of v_water. Ask which direction the boat should be crossed. What is the shortest route across the river? This question can often be seen in the reference book. The general analysis process is as follows: As shown in Figure 1, if the shortest route is to cross the river, the boat must be vertical. Crossing the river in the direction of the river bank,