题目

以10m/s的速度匀速行驶的汽车，刹车后做匀减速直线运动，加速度大小为2m/s2．则汽车刹车6s末的位移大小为（    ）                                                                                                                                  　   A． 25m            B． 24m  C． 0     D． 30m                                                                                                                                     答案：A

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