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速率沒有方向只有大小,它是運動物體經過的路程△S和通過這一路程所用時間△t的比值速度有大小也有方向,它是運動物體經過的位移△S和通過這一路程所用時間△t的比值通俗的打個比方,一個人繞著操場跑了一圈400m,用了1…
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