题干

如图甲所示,水平地面上的一物体,受到方向不变的水平推力F的作用,F的大小与时间t的关系和物体的速度v与时间t的关系如图乙所示,以下说法正确的是(   ) 

 

A:0~2秒,物体没有推动,是因为推力等于摩擦力

B:2~4秒物体做匀速直线运动

C:2~4秒物体受到的摩擦力是3N

D:4~6秒,物体受到的摩擦力与水平推力不是一对平衡力

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答案(点此获取答案解析)

A

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