The standard kilogram is a platinum-iridium cylinder 39 mm in height and 39.0 mm in diameter. What is the density of the material?
A 15,000 N car on a hydraulic lift rests on a cylinder by a piston of radius 0.20 m. If a connecting cylinder by a piston of 0.04 m radius is driven by compressed air, what force must be applied to this smaller piston in order to lift the car?