其實問題的本意是忽略空氣的作用,不管有沒有風。保持不動是指直升機不提供水平方向的推力

來源: aacdeffagg 於 2011-10-04 12:40:08 [舊帖] [給我悄悄話] 本文已被閱讀：次

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