# Physics Question

**URL:** https://forums.speedlife.net/t/physics-question/102635
**Category:** SON240sx Automotive
**Created:** [December 22, 2006, 7:23am UTC](https://forums.speedlife.net/t/physics-question/102635 "2006-12-22T07:23:38Z")
**Posts on this page:** 1
**Showing post:** 12

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### Author: ![Uniac](https://avatars.discourse-cdn.com/v4/letter/u/34f0e0/32.png) [@Uniac](https://forums.speedlife.net/u/Uniac)
#### Post date: [December 22, 2006, 8:38am UTC](https://forums.speedlife.net/t/physics-question/102635/12 "2006-12-22T08:38:42Z")

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> [@NYSPEED Softball Team](https://forums.speedlife.net/t/nyspeed-softball-team/10705/4):
>
> it doesnt have to move faster than the treadmill…the thrust will move the plane forward regardless of what the wheels are doing…and then the plane will eventually just clear the conveyor …
> 
> if you take it to the extreme and the conveyor can go infinately fast…then before the plane would achieve enough ground speed.the aircrafts tires might blow apart 🙂
> 
> its like a plane flying in extreme head wind…the plane may have 0 ground speed but is still in flight due to the airflow over the wings…
> 
> you cant defeat thrust… its newtons law

you have no lift, the plane is not moving. The plane will not fly based soley on thrust, unless thrust alone can lift the body of the plane, ie the harrier.

Use a Bullet for example, or a missle, both need to be aimed upwards and will fall tot he ground without a way to generate lift. The plane is generating no lift because the plane is not moving, fast enough to get enough air to flow over the wings to generate the lift required.

The plane may be “moving” at 500mph, but the conveyor is as well. Wind speed will remain constant. The wind will not provied enough lift at the low speeds it has at the ground to generate lift.

If a plane only needed thrust to fly, we would hoist it off the ground, turn the engine on to full and it would fly. this is not the case, even tough the engine may be at max thrust, the wings are not generating enough lift to overcome gravity. if the plane was held like this from a high enough height, and released, it WOULD eventually produce enough lift as it’s altitude decreased and speed increased. As soon as enough lift was genorated the plane would then fly.

This plane on a treadmill is genorating no lift and cannot fly.

if it was the case of only needing thrust to fly, the land speed racers would fly off trhe ground. But they do not as they are designed like a bullet and generate little lift. However a normal car, because of it’s “natural” shape will generate lift as speed increase, which is why it nededs downforce to remain on the road.

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