The production of copper foil used in printed circuit boards is accomplished by an electroforming operation in which a slowly rotating titanium drum acts as the cathode to plate copper onto its surface. The drum diameter = 500 mm and its width = 450 mm. At any moment during the process, 35% of the drum’s circumferential surface area is submerged in the electrolytic bath (the ends of the drum are insulated to prevent plating). As the copper foil exits the bath, it is peeled from the drum surface. If the thickness of the foil = 0.04 mm on the drum surface when it is peeled, and the process operates at a current of 450 amps, determine the rotational speed of the drum.