A microwave oven has a rotating plate for uniform cooking. The plate takes 8 seconds to complete one revolution and is driven by three rollers. The distance from the center of the plate to the point of contact between the plate and the roller is 12 cm. The radius of the roller is 0.5 cm. Assuming no slip between the wheels and the plate, determine the rotational speed of the rollers. Take the k-direction as perpendicular to the surface of the plate and the i-direction as left-to-right across the plate.