點解飛機起飛果時要高速衝上天空??

首先飛機要用沖力擺脫地心吸力
跟住就要到大氣分層的平流層
大氣分層有4層
由低至高:
對流層
平流層
中間層
熱層
而熱層和中間層稱高層大氣
飛機高速衝向天空
是為了擺脫對流層 衝向平流層
因為對流層天氣現象複雜
而平流層晴朗,能見度高
正確黎講係衝向大氣ge平流層
而且平流層是平流運動為主
飛機機翼有了推動,就不用較大衝力運行
這是大型機械可以在天上 飛的原因之一
因此飛機要用衝力擺脫地心吸力和對流層

2007-08-15 14:57:32 補充：
而且對流層會出現亂流較小沖力難擺脫對流層如果天氣不好就不能升空和降落

^^^ above answers are all good. Besides the aerodynamic/lift/weight points, here's an alternate answer for you.

The faster you get to higher altitude, you're much safer. Modern planes have sophisticated systems, but the higher you go, you have better radio communication reception. Most accidents happen at landings/take-offs (where air traffic is heaviest at airports). The sooner you get out of that area, the better.

Also, if there's an emergency (such as engine failure), you can glide farther with higher altitude. Imagine an engine failure at 5,000 ft vs. 20,000 ft. A pilot can have more time prepare for a crash landing at higher altitudes (such as finding a clear spot to crash land).

I plane can fly because of lift. The design of the wings will create two different pressure while air flow over it. When the pressure below the wing is higher than the one above the wings, it creates a lift. Under this rule, there must be some air flow over the wing to create lift. When it speed up, more air flow ever the wing and mroe lift is created to support the plane. That's why it need a high speed. And usually while taking off, they won't take off while there is a tailwind because less air is flowing through the wing and create less lift, so the plane will need a longer runway in this stage.

I'm not sure that if i can help you but this is my basic knowledge from aviation stuff. I could not type something complicated because my english is bad, hope i can help you. If i am wrong, i am sorry about it first

2007-08-23 05:45:58 補充：
this is not the right knowledge......好易明... don't even know what is he talking about, he is talking about atmosphere

因為佢要借助氣流把兩邊既機翼托起,咁飛機先起到飛

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