Motion changes the pressure within a fluid, and this can be difficult to predict accurately. The flow can be either smooth (streamlined) or turbulent, when the fluid is broken up into eddies; it is then harder to calculate the pressure at different points within the fluid.
Hydraulic liftA hydraulic lift (see diagram) works on the principle that an incompressible liquid transmits pressure equally in all directions. The small force f acting on area a produces pressure f/a which is converted at the much larger area A to the correspondingly larger force F so that F/A = f/a. The larger force can be used to move great weights. But the weight moves through only the small distance d.
Related category CLASSICAL MECHANICS
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