Ok, people, I'm going to have to use my amazing Photoshop skills to explain this to you people.
For this demonstration we shall need:
The point of reference is an object
NOT on the conveyer belt; it is connected to the ground and therefore stands still. Everything else is pretty self explanatory.
If you've been living under a rock and don't know what a hotwheels car is, go
here
The important thing to note about the car is that it has wheels that spin freely.
Ok, here goes.
Imagine if you were to take a hotwheels car and hold it on the surface of a treadmill with your hand. You do not push the car forward; you simply apply the force necessary to keep the car in place.
In the first case, neither your hand nor the treadmill is moving.
The treadmill is moving 0 miles per hour backwards relative to the car, and the car is moving 0 miles per hour relative to the treadmill
AND relative to the point of reference.
In the second case, we turn the treadmill on to a speed of 5 miles per hour.
The treadmill is moving 5 miles per hour backwards relative to the car, and the car is moving 5 miles per hour forward relative to the treadmill. However, the car is moving 0 miles per hour relative to the point of reference.
Now, we turn the treadmill up to 100 miles per hour.
The treadmill is moving 100 miles per hour backwards relative to the car, and the car is moving 100 miles per hour forward relative to the treadmill. However, the car is STILL moving 0 miles per hour relative to the point of reference.
NOTICE that your hand is applying almost no forward force, it is simply sitting there holding the car, regardless of the speed at which the conveyer moves.
Now, for the scientific magic
With the treadmill screaming at 100 miles per hour, you move your hand forward
RELATIVE to the point of reference at 5 miles per hour!!!!
The treadmill is moving 105 miles per hour backwards relative to the car, and the car is moving 105 miles per hour forward relative to the treadmill. BUT the car is still moving forwards at 5 miles per hour relative to the point of refrence.
Why does this happen? Simple.
As you saw in the first 3 examples, no matter how fast the treadmill moved, the car stood in place without being pushed forward. This is because the car's wheels spin freely and as long as your hand is there holding it (applying a minimal amount of force) it will stay in place. Any extra force over that minimal amount will move the car forward relative to the reference point while causing the wheels to spin even faster. Now replace the car with a plane and your hand with multiple jet engines capable of putting out thousands of pounds of thrust. The engines only need to exert a small amount of thrust of counteract the rolling resistance of the plane's wheels. Once it overcomes this rolling resistance, it will easily start moving forward, giant treadmill or not.
