来自《耶鲁大学开放课程：基础物理 第10集 第10集》

• 
  
  you're going to get V^2≠2·g·h,
  就能得到 V^2≠2·g·h
• 
  
  as you normally would.
  像平常你们会做的那样
• 
  
  You're going to get V^2=(4/3)·g·h.
  你将得到 V^2=(4/3)·g·h
• 
  
  So, it'll be moving somewhat slower than a point particle.
  所以 它会以低于质点情况下的速度运动
• 
  
  See, if it rolls without slipping,
  看 如果它无滑动地滚动
• 
  
  then you will be traveling slower at the foot of the ramp.
  在斜坡底部它将会以更小的速度运动
• 
  
  So, what did I do?
  我刚刚做了些什么呢
• 
  
  I used the Law of Conservation of Energy.
  我使用了能量守恒定律
• 
  
  That's all I did.
  那就是我刚刚所做的
• 
  
  But in finding the kinetic energy at the bottom,
  当计算斜坡底部动能的时候
• 
  
  I was careful to not just take (1/2)·m·V^2.
  我特地没有只算 (1/2)·m·V^2
• 
  
  This is the energy of a point particle,
  这是将物体视作质点时的动能