作者Gwaewluin (神无月 孝臣)
看板Physics
标题Re: [问题] 动能的来源
时间Thu Aug 20 15:14:31 2009
※ 引述《calros (【宇】)》之铭言：
: K=1/2mv^2 ＆ U=mgh
: 请问能告诉我 这2个公式的推演过程吗
: 感谢各位高手!!
这是我以前打的
基本这两个是从功推导出来的
K的过程是这样
→
→ → → → 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
U的话是计算保守场内移动所做的功
--
Deserves death! I daresay he does. Many that live deserve death. And some die
that deserve life. Can you give that to them? Then be not too eager to deal out
death in the name of justice, fearing for your own safty. Even the wise cannot
see all ends.
Gandalf to Frodo
--
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◆ From: 140.120.25.235
※ 编辑: Gwaewluin 来自: 140.120.25.235 (08/20 15:19)
1F：→ calros:感谢!! 08/20 17:24