有一個科學問題想不通

那昆蟲是會碰到車箱的

2009-04-07 23:38:46 補充：
此情況不同於你在車廂地板跳起，如你跳起，會落在原地，因為慣性定律，但那昆蟲是可以自行產生動力，所以有能力停留在半空，因此，當車廂開動，昆蟲保持原位，換言之，那昆蟲是會碰到車箱的。

如果蒼蠅在港鐵車箱裏不動,,

然而港鐵隨即移動時,,

因牛頓第一定律~

蒼蠅會撞死在最尾的車箱的車箱板上~

但若蒼蠅在港鐵車箱裏運動中,,

因車箱和蒼蠅同樣作移動,,

故作用力和慣性力互相抵銷 :

F=ma

F+(-ma)=0,,

故蒼蠅不會撞死在最尾的車箱的車箱板上

NO, it won't.
The fly inside a train compartment is in a closed system. When the train moves, the air inside the compartment moves along with the train. The fly will be carried forward by the moving air.
Should the air inside the train compartment not move together with the train, you would expect to feel a very very strong wind blowing against you when the train is moving (with wind speed of 80 km/h if the train is travelling at 80 km/h, such wind force is of gale force wing).