为了考查学生综合运用知识解决物理问题的能力 ,在中考中逐渐出现了一些开放型物理试题 .这类试题有的条件不确定 ,有的所求问题不指明 ,有的答案不唯一 ,因此 ,解答这类试题时 ,必须根据可能出现的各种情况 ,进行发散思维 ,多角度分析 ,才能得出正确的结论 .例 1　公路上甲、? In order to examine the students’ ability to use knowledge to solve physics problems, some open physics tests have appeared gradually in the middle school entrance examination. Some conditions of this kind of questions are uncertain, some of the questions asked are not specified, some of the answers are not unique, therefore, the answer In the case of such questions, divergent thinking and multi-angle analysis must be carried out according to the various situations that may arise, so as to reach a correct conclusion. Example 1 On Highway A,?