PASCAL’S PRINCIPLE Pressure can be defined as force per unit area so pushing on the fluid will increase the pressure as is done when the heart pushes on blood in the heart during contraction. This doesn’t work as well in an open system because fluid will flow away from the area of pressure. When pushing on a fluid that is enclosed, the pressure is transmitted without diminishment. This is referred to as Pascal’s principle. What it means is that the pressure is not diminished in the entirety of the fluid’s volume. What it also means is that total pressures from different sources of fluid in the same container are additive. This can be applied in hydraulic systems, such as those that operate automobile brakes. A simple hydraulic system involves a piston in a cylinder. Force is applied to a small area that gets transmitted to a larger surface area with the pressure unchanged. This is described in figure 60:
Figure 60.
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