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(单词翻译:双击或拖选)
This is a problem because a low center of gravity is more stable than a high one. Think how much easier it is to tip over a long two-by-four board balanced on one end than a block of wood the same width but only six inches high. In order to stay standing1, the center of gravity has to be over the bottom penny. If it moves out far enough so that a vertical2 line going down from that point doesn’t hit the bottom penny, the whole stack falls. And every penny you add gives more wobble, making it more likely the center of gravity will stray outside that zone, even for a moment. When it does: crash.
1 standing | |
n.持续,地位;adj.永久的,不动的,直立的,不流动的 | |
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2 vertical | |
adj.垂直的,顶点的,纵向的;n.垂直物,垂直的位置 | |
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