If you want two objects to rotate together, the easiest approach is to mechanically connect them e.g. two spindles connected by a chain or belt. If you want to control the speed then it's important to know the mechanical characteristics of the things you're trying to rotate. In the simplest case you could just use a free-running motor and gearbox to give you the required output speed. In more complex cases you would need some positional feedback and a closed loop control system to maintain the target speed. An Arduino might be used to implement that controller.