有关火车过桥、火车过隧道、两列火车车头相遇到车尾相离等问题,也是一种行程问题.在考虑速度、时间、路程三种数量关系时,必须考虑到火车的长,很多时候很难看出运动中的数量关系,对学生而言解题难度较大,因此也就成了奥赛中的热题.其实,如果我们利用点 On the train crossing the bridge, the train over the tunnel, the two trains meet the front and rear of the train leaving the other issues, but also a travel problem.In considering the speed, time, distance three kinds of relations, we must take into account the train length, a lot of time Difficult to see the number of relations in the movement, the problem-solving for students is more difficult, so it has become a hot topic in the Orsay.In fact, if we use the point