Hydraulic lift and hydraulic brakes are based on the Pascal’s law. In these devices fluids are used for transmitting pressure. In a hydraulic lift as shown in figure below two pistons are separated by the space filled with a liquid. A piston of small cross section A1 is used to exert a force F1 directly on the liquid. The pressure P = F/A in the first case.
P is transmitted throughout the liquid to the larger cylinder attached with a larger piston of area A2, which results in an upward force of P × A2. Therefore, the piston is capable of supporting a large force (large weight of, say a car, or a truck placed on the platform) F2 = PA2 =A2F1/A1
Hydrostatics topics :
What is pressure ?
Pressure variation with depth
Pascal's Law
Bulk Modulus
Shear modulus
Elastic behavior of Solids
P is transmitted throughout the liquid to the larger cylinder attached with a larger piston of area A2, which results in an upward force of P × A2. Therefore, the piston is capable of supporting a large force (large weight of, say a car, or a truck placed on the platform) F2 = PA2 =A2F1/A1
By changing the force at A1, the platform can be moved up or down. Thus, the applied force has been increased by a factor of A2/A1 and this factor is the mechanical advantage of the device.This is shown with the help of the following diagram.
Hydrostatics topics :
Problems on Bernoulli's theorem and Its Applications
Pressure variation with depth
Pascal's Law
Bulk Modulus
Shear modulus
Elastic behavior of Solids
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