[題目] 定力作功的功率(高中物理)
[領域]高中力學
[來源]參考書
[題目]有一線密度為μ的重繩靜放在光滑桌上,現以一固定速率v從一端拉動繩子,
在繩尚未全部被拉動前(也就是部分繩子等速度,部分繩子靜止),
拉動繩子的力所作的功率為何?
[瓶頸]從功率的定義出發,可以算出 P=μv^3
然而從繩子的動能變化量計算,會得到 △E=(μv^3)/2
但拉動繩子的力F所作的功應該完全轉變成繩子動能,
兩者間不應有所不同,不知道問題出在哪裡,
有請板上高人解惑,感謝!
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07/29 19:16, , 1F
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