Re: [請益] 牛頓定義動量的想法為何?
※ 引述《red0210 (讓時間去稀釋)》之銘言：
: 那我又有問題
: 為什麼明明就有個 K = 1/2 mv^2 這個"動能"的定義了
: 還要再編個 p = mv ??
: 如果說是要看被撞的感受 用動能去想不是也可以嗎!?
: 以上..
等等
動能不是用定義吧
這個m*v*v/2是算出來的東西不是
→ →
→ → → → dｖ → → dｒ
W = ∫Ｆ．dｒ = ∫mａ．dｒ = m∫-----．dｒ = m∫dｖ．-----
d t d t
→ → 1 → → 1 → → → →
= m∫dｖ．ｖ = ---m∫2dｖ．ｖ = ---m∫(dｖ．ｖ+ｖ．dｖ)
2 2
1 → → 1 v2 2 1 2 1 2
= ---m∫d(ｖ．ｖ) = ---m∫ dv = ---mv2 - ---mv1 = ΔK
2 2 v1 2 2
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