题目

 从离地面H高处投出A、B、C三个小球，使A球自由下落，B球以速                                                                                                                                                                                                                                                     率v水平抛出，C球以速率2v水平抛出，设三个小球落地时间分别tA、tB、tC，不计空气阻力，则下列说法正确的是   (　　 ) A．tA<tB<tC                                               B．tA>tB>tC C．tA<tB＝tC                                               D．tA＝tB＝tC 答案：D

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