Originally posted by: Netopia
Originally posted by: acole1
I think the point made by some above is that the plane can (and will) move forward 1MPH even while the belt is moving back 10MPH. There is nothing pulling the plane back. The belt exerts no negative force upon the plane since the wheels are free spinning.
The plane thrusts forward on the air, and the wheels spin freely underneath it as fast as they want to.
The faster the belt moves the faster the wheels move backwards, but with no effect on the plane.
Perhaps I just can't let go of reality. According to what you just laid out, if the plane was simply sitting idle and someone turned the conveyor on at 10,000 MPH in reverse, the plane would simply sit there because the tires would move independently of the plane, is that right? I guess in some hypothetical world this would work, but I don't see if working in reality.
Joe
There would have to be no friction on the spinning of the wheels... which, yes, really isn't very realistic, but is often usefull in some experiments - like 2 balls rolling down an incline, etc....
But, even with friction, there is a point at which, if the belt was going 10,000mph in reverse, the plane (sitting idle) would not just go 10,000mph in reverse (right away). It would not be a 1:1 relationship.
Also, you have to have a point of reference. What is the belt going 10,000mph in reverse to? The plane, the ground, the air?