# Physics Question **URL:** \ **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:** 9
**Author:** ![Cal](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/cal/32/5505_2.png) [@Cal](https://forums.speedlife.net/u/Cal)\ **Post date:** [December 22, 2006, 8:11am UTC](https://forums.speedlife.net/t/physics-question/102635/9 "2006-12-22T08:11:49Z")
> [@Corrugated Plastic Sheets?](https://forums.speedlife.net/t/corrugated-plastic-sheets/10704/2): > > hmmm neat question… > > problem is …an aircraft is NOT a car… > > it moves by thrust from the jets which is independant from the wheels… > > so… > > the plane and conveyors wheels could be doing whatever they want…you could even have the planes wheels going backwards… its independant of what the planes thrust is going to do…which is move the plane forward relative to the conveyor…the plane would eventually run off the conveyor…and take off like normal… > > it flys on speed relative to the ground…when the aire moves over the wing fast enough to create lift… > > this is NOT the same as a boat trying to move forward in a fast river…or a car on a conveyor… > > Thrust is the difference… I agree with you, but the question states: > This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in opposite direction). Therefore as the plane reaches full thrust and takeoff speed, the conveyor will be at the same speed. So as the plane is being pushed forward by engine thrust, it is being pulled back by the conveyor. The wheels are simply spinning without actually going anywhere. BUT: At the same time, think of an aircraft carrier. If the carrier were moving East at the same speed the plane was trying to take off in a Westward direction, the plane would not have enough speed to take off, it would plummet into the ocean because it runs out of runway fster. OK no I got it this time. Consider take off speed of a plane is 100knots. Say the conveyor had a static speed of say 100knots. In order for the plane to reach 100knots it needs to use maximim thrust. At this point they are going the same speed and there is no displacement. In order for the plane to overcome the conveyor force, it will need to genereate more thrust. In essence it needs twice the speed to take off. I don’t know, something to do with vectors right? I’ve hated physics since high school. --- _[View the full topic](https://forums.speedlife.net/t/physics-question/102635)._