dave-in-nj:
without knowing if you have a 2 pound weight on a rolling cart or 2 foot pounds, the actual motor spec cannot be determined.
each shaft will weigh roughly 2 lbs. and are held in alignment by a thrust bearing at the bottom and a regular ball bearing at the top. I suppose that equates to 4x (2lbs on independent rolling cart) ,
It looks like a variable sped DC motor with its own power supply would be ideal, with the arduino controlling the speed.