xilihutu
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加入时间: 2007/03/29
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来自: 美国
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作者：xilihutu 在 驴鸣镇 发贴, 来自 http://www.hjclub.org
Cylindrical Mirror:
This cylindrical mirror lets you see yourself as others see you.
A flat mirror will always reflect an image that is right-side up and reversed right to left. A cylindrical mirror can produce images that are flipped upside down and images that are not reversed. The image you see in a cylindrical mirror depends on the orientation of the mirror and the distance between you and the mirror.
Here's a classic tricky question:
"If a flat mirror reverses right and left, why doesn't it reverse up and down?"
The answer is that a flat mirror actually reverses in and out. That is, light that travels "in" to the mirror is bounced back "out" of the mirror. This reversal does not change up into down, but it does change right into left. Consider the outline of the hand below. Is it a right hand or a left hand? You cannot tell which hand it is unless you know whether the palm of the hand is facing "in" to the page or "out" of the page. So right and left depend on in and out.
This hand is either left or right, depending on which way the palm is facing.
作者：xilihutu 在 驴鸣镇 发贴, 来自 http://www.hjclub.org
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是你对还是我right？ |
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镜子的问题跟印章是一个道理
