hidrostatika

Hidrostatika is the branch of physics that studies liquids at rest and the forces they exert under the influence of gravity. It analyzes how pressure is distributed inside a stationary fluid, how fluids exert buoyant forces on immersed bodies, and how fluids push on container walls and other boundaries.

In a fluid at rest, pressure increases with depth. The hydrostatic equation states that the vertical rate of change of pressure is ρ g, so the pressure at depth h below a free surface is P = P0 + ρ g h, where ρ is the fluid density, g the acceleration due to gravity, and P0 the pressure at the surface (often atmospheric in open containers).

When objects are submerged, they experience buoyancy: the upward force is equal to the weight of the displaced fluid, F_b = ρ_fluid g V_submerged. This Archimedes’ principle explains why objects float, sink, or remain submerged depending on density relative to the fluid.

Pascal’s law states that pressure applied to an enclosed fluid is transmitted undiminished in all directions. This principle underlies hydraulic devices such as brakes and presses and helps explain the behavior of fluids in closed systems. Hydrostatics also covers the resultant force on submerged surfaces and the hydrostatic paradox, where the bottom force can depend only on water height rather than the total amount of liquid.

Applications span engineering, hydraulics, geophysics, and environmental science, including liquid storage, dam design, manometers, submarines, and water-supply systems. Common quantities include pressure in pascals, density in kilograms per cubic meter, and force in newtons.