题干

如图甲所示,小球从某高度处静止下落到竖直放置的轻弹簧上并压缩弹簧,弹簧始终发生弹性形变.不计空气阻力.从小球刚接触到弹簧到将弹簧压缩至最短的过程中,小球的速度v和弹簧被压缩的长度△l之间的关系如图乙所示,其中b为曲线最高点.则该过程中(   )

A:小球刚与弹簧接触时,动能最大

B:小球的重力与弹簧提供的支持力相等时,小球的速度为零

C:图象中b点对应时刻的小球重力势能最大

D:小球的速度达到最大值后,速度减小的越来越快

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D

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