Physics
Fluid Pressure and Archimedes' Force
Pressure
The pressure inside a fluid depends on depth.
- Hydrostatic pressure: p = ρ·g·h.
- Pascal's law: pressure applied to a fluid is transmitted equally in all directions.
- Hydraulic press: F₁/S₁ = F₂/S₂. It gives a gain in force.
- Normal atmospheric pressure ≈ 101 325 Pa.
Example: in water (ρ = 1000 kg/m³) at a depth of 3 m, p = 1000·10·3 = 30 000 Pa = 30 kPa.
Archimedes' Force
A body immersed in a fluid experiences an upward buoyant force:
F_A = ρ_suyuq·g·V_botgan
Example: if a body with V = 0,005 m³ is completely submerged in water, F_A = 1000·10·0,005 = 50 N.
Condition for Floating
| Condition | Result |
|---|---|
| ρ_jism < ρ_suyuq | the body floats |
| ρ_jism = ρ_suyuq | the body stays in equilibrium inside the fluid |
| ρ_jism > ρ_suyuq | the body sinks |
Floating depends on density, not on mass or volume alone. Even a heavy ship floats, because its average density is less than that of water.
- Take the fluid density ρ
- Find the depth h or the submerged volume V
- Substitute into the formula and check the units