Statement of Pascal’s law: If the pressure in a liquid is changed at a particular point, the change is transmitted to the entire liquid without being diminished in magnitude.
Application of Pascal’s law: Hydraulic lift: A practical application of Pascal’s law is the hydraulic lift which is used to lift a heavy load with a small force. It is a force Hydraulic lift multiplier. In consists of two cylinders A and B connected to each other by a horizontal pipe, filled with a liquid. They are fitted with frictionless pistons of cross sectional areas A1 and A2 (A1 > A2 ). Suppose a downward force F is applied on the smaller piston, the pressure of the liquid under this piston increase to \(P (Where, P = \frac{F_1}{A_1})\). But according to Pascal’s law, this increased pressure P is transmitted undiminished in all directions. So a pressure is exerted on piston B. Upward force on piston B is
Therefore by changing the force on the smaller piston A, the force \(\frac{A_1}{A_2}\) on the piston B has been increased by the factor and this factor is called the mechanical advantage of the lift.
