Jul 26th 2010, 13:54:30
yeh realistically the question is irrelevant due to no one makes a tread mill large enough or quick enough to stop the plane taking off,
it cant take off it the treadmill goes a million miles a hour backwards as it dosent generate enough thrust to overcome that and it would just end up going straight into a object like a house or a wall
if the treadmill is only going 10km a hour then you can easily take off,
if they are going the same speed you would just stay constant as the air wouldnt be flowing under any quicker than it just not turning on its engine or the treadmill as you would not be generating thrust going forward provided the friction applied to the wheels was equal to the thrust generated
this relies on having wheels big enough it makes a difference to otherwise the plane would just end up dragging itself forward on its normal wheels due to them being too small as the force of the plane and thrust would be greater than the applied friction from the wheels. if you had a million wheels the friction/backwards motion would stop it going forwards,
planes generate approx 10,000 pounds of thrust so the treadmill would need to generate 10,000 pounds of negative thrust or friction to keep it still or take it backwards
interesting debate tho