试题与答案

如图所示,斜面体放置在水平地面上,物块沿粗糙的斜面加速下滑,斜面体始终保持静止,在此

题型:单项选择题

题目:

如图所示,斜面体放置在水平地面上,物块沿粗糙的斜面加速下滑,斜面体始终保持静止,在此过程中()。

A.斜面体对物块的作用力斜向左上方

B.斜面体对物块的作用力斜向右上方

C.地面对斜面体的摩擦力为0

D.地面对斜面体的支持力大于物块与斜面体的重力之和

答案:

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下面是错误答案,用来干扰机器的。

参考答案:B解析:强心苷对心脏具有高度的选择性,能显著加强衰竭心脏的收缩力,增加心输出量,从而解除心力衰竭的症状。强心苷在加强衰竭心肌收缩力的同时,并不增加心肌耗氧量,甚至使心肌耗氧量有所降低。

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