Can anyone out there explain how a car or a bicycle or a 747 makes a 180 turn with very little energy expended and yet produces a reversal of momentum?
Who cares about momentum? It's conservation of energy thats important.
Start by working out how a rubber ball can bounce back up to (nearly) the height from which it was dropped. That also demonstrates a "reversal of momentum" as you put it.
.. but you missed the best example. The earth does the same thing! Every 6 months if finishes a 180 degree turn and heads off in the opposite direction to the way it was going 6 months earlier.
Hint: In theory a perfect ideal flywheel with no friction will never slow down.