如图所示光滑竖直圆槽,AP、BP、CP为通过最低点P与水平面分别成30°

如图所示光滑竖直圆槽,AP、BP、CP为通过最低点P与水平面分别成30°、45°、60°角的三个光滑斜面,与圆相交于A、B、C点.若一物体由静止分别从A、B、C滑至P点所需的时间为t1,t2,t3,则 (    )

A.t1<t2<t3                    B.t1>t2>t3

C.t1= t2= t3                      D.t1= t2<t3

 

答案

C

解析:

 

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