Pascal's law and its applications

PASCAL'S LAW, discovered by the French scientist Blaise Pascal, states that a change in pressure applied at any point of an enclosed liquid at rest is transmitted UNDIMINISHED to every other point of the liquid and to the walls of the container -- equivalently, the pressure in a fluid at rest is the same at every point at the same height. HYDRAULIC LIFT. The classic engineering application of Pascal's law is the hydraulic lift, a force multiplier used to raise a heavy load with a comparatively small applied force. It consists of two cylinders A and B, connected by a horizontal pipe and filled with a liquid, each fitted with a frictionless piston -- cylinder A carries the smaller piston, of cross-sectional area $A_1$, and cylinder B carries the much larger piston, of cross-sectional area $A_2$ (with $A_2>A_1$). Applying a downward force $F_1$ on the small piston raises the liquid pressure under it to $P=F_1/A_1$; by Pascal's law, this same increased pressure P acts, undiminished, on every part of the liquid, including under the large piston B, producing there an upward force $F_2=P\times A_2=F_1\times\dfrac{A_2}{A_1}$. So the force on the larger piston …