- 問題詳情: Lighttravelsataspeedwhichisaboutamilliontimesfasterthanthespeedofsound.Inonesecond,lighttravelsabout300,000km,butsoundtravelsonly344m.Youcangetsomeideaofthisdifferencebywatchingthestartofarace.Ifyoustandsomedistanceawayfromthestarter,yo...
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