Question

Write any two application of Pascal's law?

Answer 1

Hydraulic brakes are used in cars, lorries and motorcycles.

In a hydraulic brake system, a liquid, known as brake fluid,
is used to transmit pressure from the brake pedal to all the wheels of the vehicle.

Hydraulic Pumps

Hydraulic pumps are used to raise cars in a motor workshop.

The machine is equipped with a small cylinder connected to a large cylinder. Both cylinders are filled with oil.

Compressed air is introduced into the small cylinder in which the compressed air exerts a pressure on the surface of the oil.

Answer 2

●●●●Hydraulic press●●●●


Hydraulic press is a machine which works on Pascal’s law. It consists of two cylinders of different cross-sectional areas. They are fitted with pistons of cross-sectional areas a and A. The object to be compressed is placed over the piston of large cross-sectional area A. The force F1 is applied on the piston of small cross-sectional area a. The pressure P produced by small piston transmitted equally to large piston and a force F2 acts on A which is much larger than F1.

Press on piston of small area a is given by :

P =F1/a

Apply pascal’s law, the pressure on large piston of area A will be the same as on small piston.

P =F2/A
Comparing the above equations, we get:

F2/A= F1/a

Hence:

F2= A ×F1/a

OR

F2 = F1 ×A/a

Since the ratio is greater than 1, hence the force F2 that acts on the larger piston is greater than the force F1 acting on the smaller piston. Hydraulic systems working in this way are known as force multipliers.

Braking system in Vehicles


The braking systems of cars, buses, etc.also work on pascal’s law. The hydraulic brakes allow equal pressure to be transmitted throughout the liquid. When brake pedal is pushed, it exerts a force on the master cylinder, which increases the liquid pressure in it. The liquid pressure is transmitted equally through the liquid in the metal pipes to all the pistons of the other cylinders. Due to the increase in liquid pressure, the pistons in the cylinders move outward pressing the brake pads with the brake drums. The force of friction between the brake pads and the brake drums stops the wheels.

●●●●Hydraulic lift●●●●

In a hydraulic lift a narrow cylinder A is connected with a wider cylinder B and they are fitted with air tight pistons.It is filled with some in compressible fluid.Pressure can be applied to move the piston in the cylinder A in the downward direction.

The pressure so applied is transmitted according to pascal’s principle to the piston of the cylinder B.Consequently ,the piston B moves upward in a hydraulic lift the piston B is used as a platform for a car or any heavier object to be lifted ,like truck ,cars,also in play land etc.

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