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> 一个物体位移与时间的关系为x=5t-t 2+2(x以m为单位,t以s为单位)，关于此物体下列说法中正确的是( ) A．第2s初的速度比1s末速度小2m/s B．2s内的平均速度为4m/s C．第2s内的平均速度为2m/s D．第2s位移比第1s位移大2m

问题：

发布时间：2024-09-13

一个物体位移与时间的关系为x=5t-t ²+2(x以m为单位,t以s为单位)，关于此物体下列说法中正确的是( )

A．第2s初的速度比1s末速度小2m/s

B．2s内的平均速度为4m/s

C．第2s内的平均速度为2m/s

D．第2s位移比第1s位移大2m

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