Quote:
Originally Posted by cdcox
Where is the force coming from that keeps it from accelerating?
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Not a perfect illustration but something to work with.
Let's say there is a point
n where the vector N meets the circle. Let's add that this is the only point where the wheel meets the treadmill.
When the engines exert thrust (in direction -F) the plane tries to move forward F. Friction resists wheel point
n moving. We are assuming this friction is high enough to stop
n's motion, causing rolling and preventing sliding.
This happens because wheel point
n pushes (i.e. exerts force) against treadmill point
n. The resistance
pushes back with an equal and opposite force, stopping the wheel from sliding. The energy from this causes the wheel to rotate forward (i.e. roll).
The force from the wheel against the treadmill also pushes the treadmill, causing it to rotate backward relative to the wheel.
These forces act equally and simultaneously. All the energy involved is from the engine, transmitted through the suspension and wheels.