The small piston of a hydraulic lift has a cross-sectional area of 3.00 $\mathrm{cm}^{2}$ and its large piston has a cross-sectional area of 200 $\mathrm{cm}^{2}$ (Fig. $14.4 \mathrm{a} ) .$ What force must be applied to the small piston for the lift to raise a load of 15.0 $\mathrm{kN}$ ? (In service stations, this force is usually exerted by compressed air.)