英語聽力 學(xué)英語,練聽力,上聽力課堂! 注冊 登錄
> 在線聽力 > 英語高級聽力 > 英語時(shí)差 >  第823篇

英語時(shí)差:為什么飛盤會飛呢?

所屬教程:英語時(shí)差

瀏覽:

2021年04月03日

手機(jī)版
掃描二維碼方便學(xué)習(xí)和分享
https://online2.tingclass.net/lesson/shi0529/10000/10183/823.mp3
https://image.tingclass.net/statics/js/2012
With a gentle flick of the wrist on a warm summer day, you can launch a frisbee on a long and graceful flight. On this Moment of Science we'll learn why frisbees fly so well.

One reason is something called gyroscopic force. This is the tendency of a spinning object to maintain a stable orientation. If you throw any round object so it spins as it flies--a record album or compact disk for example--it will tend to fly something like a frisbee. If you throw it horizontally, it will stay horizontal for most of its flight. The leading edge of a CD or record is much narrower than its broad, flat surfaces, so this steady orientation helps reduce air friction.

Frisbees and compact disks have the same advantages as far as gyroscopic force is concerned, but there's another physical property that gives your frisbee an aerodynamic edge over your music collection. The top surface of a frisbee is curved. It's wider in the middle and tapers at the edges somewhat like the wing of an aircraft. This is no accident. Air moves more quickly over a curved surface than over a flat one, and this faster moving air above your frisbee has lower air pressure than the slow moving air beneath it. The higher pressure on the frisbee's bottom pushes gently upward for a longer flight, an effect known as "lift."You can even use lift to make your frisbee fly a curving path. Throw the frisbee not horizontally, but at a slight angle. The lift will push the disk in the direction the curved surface is pointing. Use a sharp enough angle, and the frisbee will swing back toward you like a boomerang!

用戶搜索

瘋狂英語 英語語法 新概念英語 走遍美國 四級聽力 英語音標(biāo) 英語入門 發(fā)音 美語 四級 新東方 七年級 賴世雄 zero是什么意思江門市十里方圓(別墅)英語學(xué)習(xí)交流群

網(wǎng)站推薦

英語翻譯英語應(yīng)急口語8000句聽歌學(xué)英語英語學(xué)習(xí)方法

  • 頻道推薦
  • |
  • 全站推薦
  • 推薦下載
  • 網(wǎng)站推薦