The top disc is sitting on top of the bottom disc, rotating in the opposite direction from it at the same angular velocity, so in classical mechanics it would be static to someone standing outside of both discs. The object is on the top disc.
The other disc is there because I want to determine...
Hypothetically, if you had an object on top of a disc on Earth that was rotating clockwise incredibly quickly such that the object had a tangential velocity of almost c, and this disc sat on another disc rotating anticlockwise with the same angular velocity, would the object feel the effects of...