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posted Jul 7, 2015, 11:33 PM by Upali Salpadoru

In ancient Sri Lanka, hydraulics were widely used in the ancient kingdoms of Anuradhapura and Polonnaruwa.[3] The discovery of the principle of the valve tower, or valve pit, (Bisokotuwa in Sinhalese) for regulating the escape of water is credited to ingenuity more than 2,000 years ago.” Extract from Wikipedia.


Fig.1 Two toys of un equal weight are balanced here.

Even in countries like China and Greece hydraulics have been used since ancient times. Hydraulics is the study of liquid flow and pressure for the benefit of mankind.

Here is how hydraulics may be used to lift a heavy load with a small effort.

A1 and A2 are two cylinders filled with oil. When a force is applied with the piston in A1 the pressure is transferred to piston A2 as shown by the arrows.

Take the areas of A1 : A2 =  1 : 10

Let the weight be  50 newtons.

As Pressure = Force/ Area, the pressure here will be 50/ 1

If the Effort balances the Load, pressure on both sides should be the same.

  Thus we get:-      

                   Then Load = 500 N

There are many applications of changing and transferring a force using fluids in this manner. Heavy machinery like the excavators, loaders and big cranes make use of this principle. The diagram attached shows how the brake system works in motor cars.

car breaks.jpg

Fig.2 Brake system in a motor car.