vfrpilotpb,
The tail rotor does not absorb or balance energy at all. It is there to exactly counter the torque that the main rotor imparts on the fuselage as it is spun. A gyro has nothing to do with it.
Basically, the main rotor does not want to spin unless pushed. The proof is how quickly it slows down if the engine is decoupled. This continuous push to keep it spinning requires that an opposite push is needed to balance the system. If the helo was a boat, and you pushed its blades around by hand, you would have to dig your shoes into the deck and lean into the blades as you push them, and your feet would push the boat around in the opposite rototion.
The tail rotor is used to allow the "boat" to grab the water and push back to keep the boat pointing straight.
You ground machinery comparison isn't correct because that machine is tied to the ground, so this side push is free, and you can't see it. Watch the engine of your car rotate in its mounts as you goose the throttle. If the car were not sitting on the ground but floating in the air, the car would roll in the opposite direction!
The gyro in that ground machine is probably used to smooth out the rotation by adding mass, a common trick.