╭──────────── 提醒：版規三及版規四 ─────────────╮ │解題文需附上自己的解題過程或自己對題目的理解 │ │問題文需先自行查過網路資料並附上對資料的初步理解 │ │問題獲得回答後也勿任意刪除文章，並適度的向回答者表達感謝之意 │ ╰──────────────────────────閱讀後可用ctrl+y刪除╯ 【出處】(習題或問題的出處) halliday 第十版 chp8 78題 【題目】(題目的文字敘述，如有圖片亦可提供圖片) 78 At a certain factory, 300 kg crates are dropped vertically from a packing machine onto a conveyor belt moving at 1.20 m/s (Fig. 8-62). (A motor maintains the belt’s constant speed.) The coeffi- cient of kinetic friction between the belt and each crate is 0.400. After a short time, slipping between the belt and the crate ceases, and the crate then moves along with the belt. For the period of time during which the crate is being brought to rest relative to the belt, calculate, for a coordinate system at rest in the factory, (a) the kinetic energy supplied to the crate, (b) the magnitude of the ki- netic frictional force acting on the crate, and (c) the energy sup- plied by the motor. (d) Explain why answers (a) and (c) differ. 【瓶頸】(解題瓶頸或思考脈絡，請盡量詳述以利回答者知道要從何處講解指導) (錯誤示範：第X題我不會，求詳解) (錯誤示範：acceleration of gravity是什麼意思我看不懂) (正確示範：我算出來的答案好像不太對，這是我的計算過程，哪裡出問題?) (c)選項答案是(a)的兩倍，詳解說馬達做的功是摩擦力做的功跟動能的增加，但是摩擦力 做的功不是轉換成動能了嗎？ 有點無法理解 --

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