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咸鱼的世界
21 Feb 2021, 15:27
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冷知识：长度单位m的定义来自钟摆。人们先把1s确定为了一天的1/86400，然后校准摆钟，让它1s摆一下，这时的摆长就定义为了1m。这样根据单摆公式，重力加速度g自然就成了π²约等于9.86。当然后来这些单位重新定义了，数值有了变化，不过差的也不多。
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