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# PascalŌĆÖs law and its applications

PascalŌĆÖs law is 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.

PascalŌĆÖs law and its applications

The French scientist Blaise Pascal observed that the pressure in a fluid at rest is the same at all points if they are at the same height. Statement of PascalŌĆÖs law is 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 PascalŌĆÖs law

Hydraulic lift A practical application of PascalŌĆÖs law is the hydraulic lift which is used to lift a heavy load with a small force. It is a force multiplier. It consists of two cylinders A and B connected to each other by a horizontal pipe, filled with a liquid (Figure 7.12). They are fitted with frictionless pistons of cross sectional areas A1 and A2 (A2 > A1). Suppose a downward force F is applied on the smaller piston, the pressure of the liquid under this piston increases to P(where, p=F1/A1).But according  to PascalŌĆÖs 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 on the piston B has been increased by the factor A1/A2 and this factor is called the mechanical advantage of the lift.

### EXAMPLE 7.7

Two pistons of a hydraulic lift have diameters of 60 cm and 5 cm. What is the force exerted by the larger piston when 50 N is placed on the smaller piston?

### Solution

Since, the diameter of the pistons are given, we can calculate the radius of the piston This means, with the force of 50 N, the force of 7200 N can be lifted.

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11th Physics : UNIT 7 : Properties of Matter : PascalŌĆÖs law and its applications |