Hydraulic lift is a machine which is based on Pascal's law. In these devices fluids are used for transmitting presure.
Hydraulic lift consists of two cylinders of different cross-sectional areas connected with a pipe. The cylinders are filled with incompressible liquid and frictionless pistons are fitted in both the cylinders as shown in figure below.
Let 'a' and 'A' be the area of cross-section of smaller piston and bigger piston respectively. The load to be lifted is placed on bigger cross-section and effort is applied on smaller piston.
Let a force 'f' be applied on the smaller piston.
The pressure exerted by f on piston is,
Now, according to Pascal's law, the pressure transmitted to bigger piston is also P.
Thus, force on bigger piston is, given by,
That is, the transmitted force gets multiplied by a factor of applied force.