来自《耶鲁大学开放课程：基础物理 第4集 第4集》

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  I push it, it's not moving.
  我推了它 它没有动
• 
  
  But if I push hard enough it will move.
  但是如果我推力足够大的话它就会动
• 
  
  What's happening before it moves?
  在它动之前发生了什么呢
• 
  
  I'm applying a force and I'm getting nothing in return for it.
  我施加了一个力 却没有得到什么效果
• 
  
  So I know there is another force opposing what I do,
  所以我知道有另一个力在阻止我推讲桌
• 
  
  and that's called "a force of static friction".
  它叫做 "静摩擦力"
• 
  
  So, static friction is when the body is not moving.
  静摩擦力是物体没有移动时才有的
• 
  
  So, I'm applying a force F.
  我施加一个力 F
• 
  
  Let me give it some other name, f.
  我还是给它换一个符号吧 f
• 
  
  No, that's also bad,
  这也不好
• 
  
  f was the name for friction.
  f 是摩擦力的符号
• 
  
  So, I'm going to apply a force called Fme.
  所以我要施加这个力叫做 Fme