来自《耶鲁大学开放课程：基础物理 第8集 第8集》

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  These are no great secrets; you'll find them in any textbook.
  这不是什么秘密 任何课本里都有
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  If you cannot follow my handwriting
  如果你跟不上我写
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  or you're running out of time,
  或者你没有时间
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  just what you should be understanding now
  那么你只须懂得
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  is that there are formulae for the final velocity
  这些是求解末状态的速度的公式
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  when the collision is totally elastic, or totally inelastic.
  当碰撞是完全弹性的 或是完全非弹性的
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  If they're totally inelastic,
  如果是完全非弹性的
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  it's what I wrote there, v' is something.
  那就是我现在所写的 v'
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  The totally elastic you have a formula like this one.
  对于完全弹性碰撞你有这个公式
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  So, here you just replace everywhere
  这里你将所有
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  you saw an m1 you put an m2,
  式中的 m1 换成 m2
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  Don't waste too much time writing this.
  不要花太多时间来把它抄下来