Physics:Newton's Apple（17）
On this episode of Newton's Apple， we shall find answers to the questions: First， we will ride the rails to get the insight of how a roller coaster was made. Second， my mother and my teacher are always saying how dangerous smoking is. They say millions of people smoke and thousands of them die of it every year. If smoking is so unhealthy， why is it so hard for some people to stop? And third， exactly how does an eraser work?
- Added：2006
- Country：America
- Duration：30
- Time of update：2011/8/16 10:24:22