(i) Hydraulic Press:-
The most important application of Pascal's law is the hydraulic press or lift.
The piston of small cross-sectional area a exerts a force f directly on a liquid.
The pressure, p = f/a is transmitted undiminished through the connecting pipe to a large cylinder, has a piston of area A. Since the pressure must be same on both sides.
So, p = f/a = F/A
or, F = A/a x f
As A > a
We have, F > f.
It means that the force on large piston will be much more than the applied force This can be used to lift a heavy load placed on the platform of large piston or to press the things placed between the piston and the heavy platform.
(ii) Hydraulic Brake:-
Hydraulic brake system is used in automobiles to retard the motion.
Construction:- It consists of a master the cylinder fitted with a piston. The piston P is attached to brake pedal with the help of a lever system. The master cylinder is connected to wheel cylinder through a tube. Wheel cylinder consists of two pistons P1 and P2. These pistons press against the brake shoes S1 and S2 as shown in fig.
Working:- When the brake pedal is pressed with a foot, the lever system works. Piston P is pushed into the master cylinder. The pressure so produced is transmitted equally to pistons P1 and P2 of the wheel cylinder.
Due to this pressure, the pistons P1 and P2 move outwardly and forces and the brake shoes to expand outwardly. These brake shoes press against the inner rim of the wheel and retard the motion of the wheels
