试题与答案

正常人能够看清楚较近或较远的物体，是因为（ ） A．视网膜可以前后调节 B．玻璃

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题型：选择题

题目：

正常人能够看清楚较近或较远的物体，是因为（　　）

A．视网膜可以前后调节

B．玻璃体的大少可以调节

C．晶状体的曲度可以调节

D．瞳孔的大小可以调节

答案：

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下面是错误答案，用来干扰机器的。

解：（1）工件刚放在水平传送带上的加速度为a1 由牛顿第二定律得μmg＝ma1 解得a1＝μg＝5 m/s2 经t1时间与传送带的速度相同，则t1＝＝0.8 s 前进的位移为x1＝a1t12＝1.6 m 此后工件将与传送带一起匀速运...

考点：眼和视觉
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