For this problem, I don't understand how can the system be at rest and immediately after placing the mass, to move with constant speed. But anyways, can you tell me please how to proceed? On the hanging mass, there is mg acting and T the tension of the rope. On the flywheel, the tension of the rope is acting and the friction of the bearings. I have no clue what the tension of the rope is. I wanted to say that opposite to the mg, is the friction and the inertial force of the flywheel, but I am not familiar with calculations of the inertial force. Any idea?