一、准备性练习解答相遇问题的关键在于求出两个物体的速度和.它的基本数量关系式是“速度和×相遇时间=两地距离”,显然,这是单一物体运动中基本数量关系“速度×时间=路程”的发展.在教学“相遇问题”之前,应进行行程问题中三量关系的基本训练,为学习“相遇问题”作好铺垫.1.学校长方形操场的长是60米,宽40米.小明 First, the preparatory exercises to answer the key to meet the problem is to find the speed of two objects and its basic relationship is the number of “speed and × encounter time = distance between the two,” Obviously, this is the basic relationship between a single object movement “Speed ​​× time = distance” development.In the teaching of “encounter” before the trip should be carried out in the relationship between the three basic training to pave the way for the study of “encounter.” The length of the school rectangular playground is 60 meters , 40 meters wide