# 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:** 20\ **Page:** 8
**Author:** ![Osad](https://avatars.discourse-cdn.com/v4/letter/o/3ab097/32.png) [@Osad](https://forums.speedlife.net/u/Osad)\ **Post date:** [December 25, 2006, 7:10pm UTC](https://forums.speedlife.net/t/physics-question/102635/141 "2006-12-25T19:10:06Z")
Hmm, i musta worded it wrong before… Thats the idea^^ ---
**Author:** ![prodigy](https://avatars.discourse-cdn.com/v4/letter/p/8491ac/32.png) [@prodigy](https://forums.speedlife.net/u/prodigy)\ **Post date:** [December 26, 2006, 12:09pm UTC](https://forums.speedlife.net/t/physics-question/102635/142 "2006-12-26T12:09:36Z")
Now, it’s worth mentioning that we’re assuming a perfect testing condition in which no friction exists between the belt and the tires, or the bearings on the wheels themselves. So, in actuality the conveyor belt speed will in-fact effect the plane’s ability to take off as it causes drag. The ability of the plane to generate enough thrust will govern its ultimate ability to take flight. If it can’t produce enough thrust by the end of the runway, it may be overcome by the aforementioned friction between the wheels/bearings and the conveyor belt, and crash. Furthermore, if the pilot(s) decided to hit the wheel brakes while moving forward, the plane would be flung backwards by the belt. 😃 ---
**Author:** ![prodigy](https://avatars.discourse-cdn.com/v4/letter/p/8491ac/32.png) [@prodigy](https://forums.speedlife.net/u/prodigy)\ **Post date:** [December 26, 2006, 12:10pm UTC](https://forums.speedlife.net/t/physics-question/102635/143 "2006-12-26T12:10:29Z")
But perhaps I’m just splitting hairs now. 😉 ---
**Author:** ![AppleSauce](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/applesauce/32/5521_2.png) [@AppleSauce](https://forums.speedlife.net/u/AppleSauce)\ **Post date:** [December 26, 2006, 12:48pm UTC](https://forums.speedlife.net/t/physics-question/102635/144 "2006-12-26T12:48:22Z")
> [@prodigy"](#): > > Now, it’s worth mentioning that we’re assuming a perfect testing condition in which no friction exists between the belt and the tires, or the bearings on the wheels themselves. So, in actuality the conveyor belt speed will in-fact effect the plane’s ability to take off as it causes drag. > > The ability of the plane to generate enough thrust will govern its ultimate ability to take flight. If it can’t produce enough thrust by the end of the runway, it may be overcome by the aforementioned friction between the wheels/bearings and the conveyor belt, and crash. > > Furthermore, if the pilot(s) decided to hit the wheel brakes while moving forward, the plane would be flung backwards by the belt. 😃 The belt matches the speed of the plane not the wheels. So the wheels will only be spinning at twice the speed of the plane. If they hit the brakes to slow down the plane, the belt will also slow down because it’s matching the speed of the plane. lol @ the engineer students that got the question wrong. ---
**Author:** ![prodigy](https://avatars.discourse-cdn.com/v4/letter/p/8491ac/32.png) [@prodigy](https://forums.speedlife.net/u/prodigy)\ **Post date:** [December 26, 2006, 12:51pm UTC](https://forums.speedlife.net/t/physics-question/102635/145 "2006-12-26T12:51:49Z")
> [@Skelly checking in](https://forums.speedlife.net/t/skelly-checking-in/10716/22): > > The belt matches the speed of the plane not the wheels. Oh, good point! Right you are. ---
**Author:** ![ADAMH](https://avatars.discourse-cdn.com/v4/letter/a/71e660/32.png) [@ADAMH](https://forums.speedlife.net/u/ADAMH)\ **Post date:** [December 27, 2006, 5:48am UTC](https://forums.speedlife.net/t/physics-question/102635/146 "2006-12-27T05:48:27Z")
So kidlets… I see some of you now know the plane will take off…and still a few are clinging to the hope that it wont 🙂 ---
**Author:** ![ADAM](https://avatars.discourse-cdn.com/v4/letter/a/4af34b/32.png) [@ADAM](https://forums.speedlife.net/u/ADAM)\ **Post date:** [December 27, 2006, 5:51am UTC](https://forums.speedlife.net/t/physics-question/102635/147 "2006-12-27T05:51:35Z")
bahh finally found my password for my main account… ---
**Author:** ![krgoodwin](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/krgoodwin/32/5559_2.png) [@krgoodwin](https://forums.speedlife.net/u/krgoodwin)\ **Post date:** [December 28, 2006, 12:30am UTC](https://forums.speedlife.net/t/physics-question/102635/148 "2006-12-28T00:30:50Z")
> [@Does he have awd?](https://forums.speedlife.net/t/does-he-have-awd/10741/3): > > So kidlets… > > I see some of you now know the plane will take off…and still a few are clinging to the hope that it wont 🙂 why will it take off if there is no lift? if your going to attempt to answer this don’t start talking about treadmills and shit. just tell me how a plane creating no lift will take off. EDIT: i know if you put a big enough jet engine on anything it will fly, but were talking an unmodified airplane. ---
**Author:** ![Solarian](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/solarian/32/5514_2.png) [@Solarian](https://forums.speedlife.net/u/Solarian)\ **Post date:** [December 28, 2006, 1:24am UTC](https://forums.speedlife.net/t/physics-question/102635/149 "2006-12-28T01:24:24Z")
> [@Lamborghini JALPA](https://forums.speedlife.net/t/lamborghini-jalpa/10706/20): > > why will it take off if there is no lift? > > if your going to attempt to answer this don’t start talking about treadmills and shit. just tell me how a plane creating no lift will take off. > > EDIT: i know if you put a big enough jet engine on anything it will fly, but were talking an unmodified airplane. That’s what your basic mistake is. You’re assuming the plane will not create any lift. I was thinking the same thing until I stopped to think about it. It will, just as much as normally. The treadmill does not affect the normal operation of the airplane in the slightest. Plane ignores treadmill, speeds down treadmill/runway odd contraption, since it doesn’t use shaftwork transmitted to wheels, but thrust, and it generates lift as it normally would, and takes off as it normally would. ---
**Author:** ![krgoodwin](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/krgoodwin/32/5559_2.png) [@krgoodwin](https://forums.speedlife.net/u/krgoodwin)\ **Post date:** [December 28, 2006, 12:03pm UTC](https://forums.speedlife.net/t/physics-question/102635/150 "2006-12-28T12:03:45Z")
> [@Now I've been hit pretty hard before](https://forums.speedlife.net/t/now-ive-been-hit-pretty-hard-before/10748/2): > > That’s what your basic mistake is. You’re assuming the plane will not create any lift. I was thinking the same thing until I stopped to think about it. It will, just as much as normally. The treadmill does not affect the normal operation of the airplane in the slightest. Plane ignores treadmill, speeds down treadmill/runway odd contraption, since it doesn’t use shaftwork transmitted to wheels, but thrust, and it generates lift as it normally would, and takes off as it normally would. well yes, thats all well and good but. lift is created by the plane moving forward. the whole point of the treadmill is for the plane to stand still. lift is created by air moving past the wings. i mentioned before that you theoreticly could create lift by plancing very large engines infront of the wings. so the engines would push air over the wings and create lift. then the plane would fly. but you would need very large engines and they would most likely melt or tear apart the wings, so its basicly a physical imposibililty to create such a plane. propeller planes excluded since they cannt create enough thrust. the bottom line is the plane needs to be moving forward to create lift. the whole point of this experiment is to keep the plane still. without air moving past the wings there is no lift and in turn there is no takeoff. Solarian: how does the plane generate lift as it normaly would? ---
**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 28, 2006, 12:26pm UTC](https://forums.speedlife.net/t/physics-question/102635/151 "2006-12-28T12:26:27Z")
^ Stop, just stop. The plane moves forward, since it does not matter what the ground/treadmill is doing. ---
**Author:** ![Solarian](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/solarian/32/5514_2.png) [@Solarian](https://forums.speedlife.net/u/Solarian)\ **Post date:** [December 28, 2006, 6:10pm UTC](https://forums.speedlife.net/t/physics-question/102635/152 "2006-12-28T18:10:00Z")
Yea. Treadmill doesn’t mean shit. Airplanes do not use wheels to propel themselves forward. ---
**Author:** ![krgoodwin](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/krgoodwin/32/5559_2.png) [@krgoodwin](https://forums.speedlife.net/u/krgoodwin)\ **Post date:** [December 28, 2006, 6:22pm UTC](https://forums.speedlife.net/t/physics-question/102635/153 "2006-12-28T18:22:16Z")
well yea, but if there is no lift being created then the plane will act just as a car (one thats powered by a rocket but a car all the same). are you saying a rocket powered car will drive right off a treadmill? just becasue it has turbines propelling it doesnt mean you can ignore the laws of gravity and friction. if the jet had its engines off and you run the treadmill it will just sit there and move backwards with the treadmill. now apply equal force (in this case a jet engine) in the oposite direction and it will cancel out the backwards movement. leaving the plane sitting completely still. i agree the wheels have nothing to do with making the plane move but untill the plane gets up enough speed to create lift it just shoves itself along the ground like a car. ---
**Author:** ![Solarian](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/solarian/32/5514_2.png) [@Solarian](https://forums.speedlife.net/u/Solarian)\ **Post date:** [December 28, 2006, 6:32pm UTC](https://forums.speedlife.net/t/physics-question/102635/154 "2006-12-28T18:32:07Z")
> [@hello new friend! I shall call you Grignard and feed you prizzalicious pringles](https://forums.speedlife.net/t/hello-new-friend-i-shall-call-you-grignard-and-feed-you-prizzalicious-pringles/10736/14): > > well yea, but if there is no lift being created then the plane will act just as a car (one thats powered by a rocket but a car all the same). are you saying a rocket powered car will drive right off a treadmill? just becasue it has turbines propelling it doesnt mean you can ignore the laws of gravity and friction. if the jet had its engines off and you run the treadmill it will just sit there and move backwards with the treadmill. now apply equal force (in this case a jet engine) in the oposite direction and it will cancel out the backwards movement. leaving the plane sitting completely still. i agree the wheels have nothing to do with making the plane move but untill the plane gets up enough speed to create lift it just shoves itself along the ground like a car. Lift IS being created. Jeesus. It won’t sit there and move backwards with the treadmill! There is no equal force! The treadmill applies a negligibly small force of friction in the rearward direction. The turbines apply a ginormous force in the forward direction. Plane goes forward. IT MAKES LIFT B/C IT GOES FORWARD. ---
**Author:** ![krgoodwin](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/krgoodwin/32/5559_2.png) [@krgoodwin](https://forums.speedlife.net/u/krgoodwin)\ **Post date:** [December 28, 2006, 6:35pm UTC](https://forums.speedlife.net/t/physics-question/102635/155 "2006-12-28T18:35:29Z")
the whole point of it being on the treadmill is that it will run backwards under the plane to stop it from gathering speed and in turn creating lift. ---
**Author:** ![Solarian](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/solarian/32/5514_2.png) [@Solarian](https://forums.speedlife.net/u/Solarian)\ **Post date:** [December 28, 2006, 6:40pm UTC](https://forums.speedlife.net/t/physics-question/102635/156 "2006-12-28T18:40:38Z")
No, it isn’t. ---
**Author:** ![Osad](https://avatars.discourse-cdn.com/v4/letter/o/3ab097/32.png) [@Osad](https://forums.speedlife.net/u/Osad)\ **Post date:** [December 28, 2006, 7:30pm UTC](https://forums.speedlife.net/t/physics-question/102635/157 "2006-12-28T19:30:58Z")
OMGWTFBBQ kyle!!! I spent a good 30 minutes trying to explain it to him, he is set in his ways… YOU’RE WRONG MAN, im sorry to break it to you. Lift WILLLLLLLLLLLLLL be created because the plane will move forward using thrust, the wheels will just spin indepentantly in the opposite direction as the plane, but will have ZERO bearing on the plane’s movement since they are independant!!! ---
**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 28, 2006, 9:36pm UTC](https://forums.speedlife.net/t/physics-question/102635/158 "2006-12-28T21:36:12Z")
> [@kingsario's first kill of the year......Viper anyone?](https://forums.speedlife.net/t/kingsarios-first-kill-of-the-year-viper-anyone/10753/13): > > the whole point of it being on the treadmill is that it will run backwards under the plane to stop it from gathering speed and in turn creating lift. Furthermore . . . . … . . . . . . . Go paint something. ---
**Author:** ![nocwage](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/nocwage/32/5489_2.png) [@nocwage](https://forums.speedlife.net/u/nocwage)\ **Post date:** [December 29, 2006, 7:41am UTC](https://forums.speedlife.net/t/physics-question/102635/159 "2006-12-29T07:41:50Z")
Please remember that ‘rockets’ also work in DEEP SPACE where there isn’t anything to ‘push’ against. Newton’s 3rd law ftw. F=ma The only force being applied to the runway by the Jet is it’s own weight being pulled down by gravity. The FORWARD motion of the jet is due the thrust generated by the engines throwing mass out the back of them. It’s not ‘pushing’ on the air behind it either… No matter what the ‘ground’ is doing the MASS of the Jet is being pushed forward by the MASS the engines are throwing backwards ‘every action has an equal an opposite reaction’ I’m glad I didn’t read this thread until today… ---
**Author:** ![big-byrd](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/big-byrd/32/3192_2.png) [@big-byrd](https://forums.speedlife.net/u/big-byrd)\ **Post date:** [December 30, 2006, 2:12am UTC](https://forums.speedlife.net/t/physics-question/102635/160 "2006-12-30T02:12:22Z")
i get it now. when people were saying thrust is independent of the wheels, i didn’t quite follow. now i understand. it’s not like a car where the motor outputs power directly to the wheels. the jet would be propelled forward, and the “treadmill” would only cause the wheels to spin more quickly than on the ground (if at all), but would still allow the plane to leave the belt. when nocwage stated newton’s third law, it made sense. this law applies to other cases as well, such as, for example, a car on the same treadmill. the motor outputs power to the wheels which exert a centripetal force allowing the car to move (relating torque and force), compared to a more linear force being produced by the turbines. it’s more along the lines of where the power is coming from, and in turn, where the force is being applied on the free body in question that makes the difference. and that difference is the plane’s turbines produce power, and like nocwage stated, the flow of gas mass propels the plane - the wheels can spin freely as they will. with a car, the wheels are connected to the power source, so speed and motion depend on force coming directly from them. i take back my previous statement - the plane will leave the belt, drive down the rest of the runway, and take off. [Previous page](https://forums.speedlife.net/t/physics-question/102635.md?page=7) [Next page](https://forums.speedlife.net/t/physics-question/102635.md?page=9)