Download
1 / 8
230 likes | 739 Views
Fluid Statics. Why do your ears hurt when you dive deep into a pool, and how can steel float on water?. Fluid statics: pressure and density. Pressure is Force/Area (N/m 2 = Pascals) A thumb tack is a good way to feel the difference between Force and pressure.
E N D
Fluid Statics Why do your ears hurt when you dive deep into a pool, and how can steel float on water?
Fluid statics: pressure and density • Pressure is Force/Area (N/m2 = Pascals) • A thumb tack is a good way to feel the difference between Force and pressure. • The atmosphere has a constant nominal pressure of 1.01 x 105 Pa (or 1 atm)
Fluid Statics: Pressure and Density • Density ρ = mass/volume • ρ(water) = 1000 kg/m3 • ρ(aluminum) = 2700 kg/m3 • ρ(gold) = 19300 kg/m3
Fluid Statics: change in pressure with increased depth • The deeper you dive into a pool the greater the pressure is. • Increased pressure Pgauge = ρgh = pressure due to the weight of the fluid at a given depth h. • The gauge pressure is the amount of increase in pressure compared to the surface (typically the surface pressure is atmosphere)
Hydrostatic pressure • Pressure in a fluid • Pgauge = ρgh • P=Pgauge + Psurface • ( Psurface= Patm)
Fluid Pressure increase with depth • The total pressure at a given depth is P=Pgauge + Psurface (where Psurface usually means Patm) • Fluid pressure depends on depth and not on the shape of the container.
Buoyant Forces and Archimedes Principle (280 B.C. Greek scientist) • The buoyant Force pushing up by a fluid = weight of the fluid displaced • To calculate the weight of the fluid multiply the fluid density (ρ) by the displaced Volume and by g • Fbuoyant = ρVg = weight of the fluid
Archimedes principle Buoyant force
