Journal daniil's Journal: An airplane on a runway with a moving surface 12
It might not be Tuesday today, but still, here's an old (yet still good) physics problem for you to take a crack at:
"An airplane (jet or turboprop) is standing on a runway with a moving surface (like a conveyer belt). The surface can move in the opposite direction to the plane, that is, towards it. It has a control system that tracks the speed of the plane and adjusts the speed of the conveyer belt in such a way that the speed at which the wheels of the plane rotate would be equal (but the opposite) to the speed of the conveyer belt. Can the plane take off from this strip?"
No.... (Score:2)
Re: (Score:2)
Yes! (Score:1)
The only effect the conveyor belt will have on the plane will be whatever friction is inherent in the wheels when the breaks are not applied. If the wheels are sufficiently frictionless, the plane will have no trouble taking off.
Think about it...If you stand on a largish patch of ice, and attempt to fly a kite, will you move, despite not having applied lateral force t
Re: (Score:2)
A plane's thrust does indeed come from a prop or jet, but it can also come from anything else that moves it (ie, a catapult a la Navy aviation).
Flight and thrust are different, however. The four forces acting on any aircraft is Lift, Weight, Thrust, and Drag. Flying occurs when the aircraft's weight is offset by it's Lift. If there is a net positive amount of Lift then the aircraft climbs. A net negative and it descends. If the Weight equals Lift, then the plane is in level flight.
Lif
Re: (Score:1)
As long as the engines apply forward thrust, the plane will accelerate forward, regardless of how quickly or slowly the wheels move. And as the plane moves forward, lift will be generated.
That said, taking off on a moving surface would be a pain in the butt, because wheels aren't entirely frictionless.
Depends (Score:1)
It depends on how much air is passing over the wings. You need air movement over the wings to generate lift, the forward momentum is what usually does this. If there was a 250 km/h wind hitting the plane head-on while it was on your treadmill: sure.
Re: (Score:2)
The correct answer, of course, is that the plane will take off when the post count in the thread discussing this problem reaches 250.
Re: (Score:2)
Afterburners ho! (Score:2)
Yes (Score:2)
That's how it
Re: (Score:2)
Depends... (Score:1)