题目

新冠肺炎疫情在国内得到有效控制，游乐场陆续开放。在游乐场中，有一种大型游戏器械叫“跳楼机”，如图所示。参加游戏的游客被安全带固定在座椅上，由电动机将座椅沿光滑的竖直轨道提升到离地面75m高处由静止释放。座椅沿轨道做自由落体运动20m后，开始受到恒定制动力而立即做匀减速运动，且下落到离地面5m高处时速度刚好减小到零。然后再让座椅以相当缓慢的速度稳稳下落，将游客送回地面。（g＝10m/s2）求： （1） 座椅做自由落体I can’t say for sure that Malcolm _______ on such an important role if he ________.（ ） A. would take; had survived　　　　 B. would have taken; survived C. would take; could have survived　 D. would have taken; had survived