Originally Posted by
FBinNY
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The spinning wheel also produces drag forces with no net horizontal vector. Keeping it as simple as possible, the spokes are pushing vertically across the moving stream upward in back, and downward in front. These cancel and don't affect the sled, but it does take power to maintain this motion.
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Yes, there has to be power to overcome the drag of spinning.
But where does it come from?
The force applied backwards to the contact patch, which spins the wheel.
Right?
OK, but the wheel isn't accelerating backwards, so there must be a force applied to hold the wheel in place, even though it's spinning about its axle.
So where's the forward force to hold the wheel in place come from?