题目

These animals could be likely to be frightened when there is a sudden loud noise. → these animals could be frightened when there is a sudden loud noise. 答案：【1】It is likely that“频闪摄影”是研究物体运动时常用的一种实验方法．照相机每隔一定的时间曝光一次，记录下物体的位置．如下图所示为甲、乙两辆汽车在平直公路上行驶时各自的频闪照片，试根据照片分析：（1）甲车做什么运动？判断依据是什么？（2）求出乙车在10s﹣20s段的速度．