When a force is applied onto a liquid, the pressure created in the liquid acts in all directions. This is because when liquid is at a standstill, matter in the liquid is distributed evenly, and because of this, pressure is also distributed throughout equally. This property of liquid is captured in the hydraulic principle, which is used widely in hydraulic jacks and hydraulic brakes. The principle is based on the formula: F1/A1 = F2/A2
A small force F1 applied on area A1 is transferred onto a liquid and then onto on an area A2, which subsequently produces a huge force F2.
Note: The larger the area, the larger the force is, and thus, a greater weight can be supported.
Eg: A force of 2N is applied on area of 1m2. If the area on the other end is 10m2, what is the force generated at the same end?
10 times more, which is 2N x 10 = 20N
Also, pressure in liquid is seen as energy per unit volume (using the definition of work). The relationship can be easily explained by the Bernoulli's Equation.
P = Force/Area = F/A = (F x d)/(A x d) = W/V = Energy/Volume