来自《耶鲁大学开放课程：基础物理 第8集 第8集》

• 
  
  in the y direction,
  方向为 Y 轴方向
• 
  
  and it's just a projectile problem.
  这一个简单的抛射问题
• 
  
  And I repeat once more, for emphasis,
  我再重复一次作为强调
• 
  
  that if this object broke into two objects,
  如果这个物体破裂为两部分
• 
  
  typically what'll happen
  一般来说接下来的情况是
• 
  
  is one will fly there and one will land here,
  一部分飞到这里 另一部分掉在这里
• 
  
  but at every instant if you found their center of mass,
  但在任一时刻 如果你寻找它们的质心
• 
  
  you will find it proceeds as if nothing happened.
  你会发现分裂过程似乎并未发生
• 
  
  For example, if you have an explosive device
  例如 如果你用一个爆炸装置
• 
  
  that blows them apart,
  将它炸开
• 
  
  and the pieces are all flying,
  所有的碎片四下乱飞
• 
  
  but that's just coming from one part of the piece pushing on
  但其中的推力只是源于一个碎片