Originally Posted by
boomhauer
The tension in the spoke is the constant force, not the force from the pedals.
And? Yes, the tension from the spoke is the force pulling any given point from a straight line into a circular path. That still means that any given point on the wheel at any given time is experiencing acceleration. Without force from the pedals, the wheel stops.
Originally Posted by
boomhauer
A satellite in space doesn't need a constant tangential force to keep rotating around the earth , only the "tension" from gravity.
Entirely different system. The satellite has reached sufficient speed that it misses the earth when it starts to fall back down. The earth is pulling it down but it keeps missing the earth. Because it is moving in a vacuum, it continues until such time as something changes the speed.