一个做匀变速直线运动的物体经时间Δt后又回到原处,回到原处时的

一个做匀变速直线运动的物体经时间Δt后又回到原处,回到原处时的速率和初速度大小相等,都是v,但运动方向相反,则这个物体在Δt内的加速度大小是

A       B0       C       D.无法确定

答案

C

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