题目

Although there were so many people in the square, I could ______ my friend.    A. pick up                      B. pick out                           C. make up                         D. set out 答案：B（12分）汽车刹车前速度为10m/s,刹车获得的加速度大小为2m/s2。求:（1）汽车刹车开始后20s内滑行的距离;（2）静止前最后2.5s内汽车滑行的距离。