6．动能相等质量不等的两个物体A、B，m_A>m_B，A、B均在动摩擦因数相同的水平地面上滑行，滑行距离分别为S_A、S_B后停下，则                                                                               （    ）

       A．S_A>S_B                                                                                                B．B滑行时间短

       C．S­_A<S_B                                                                                                D．它们克服摩擦力做功一样多