题目

滑雪运动员由斜坡高速向下滑行过程中的v﹣t图象如图所示，则由图象中AB段曲线可知，运动员在此过程中（    ）                                                                                                                                                                                        　   A． 做匀变速曲线运动      B． 做变加速运动 　   C． 所受力的合力不断增大     D．    机械能守恒                                                                                                                                      答案：B

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