Physics - Fluids

Pressure

P = F/A, force over a certain area

P

pressure (Pa)

F

force (N)

A

area (m²)

Pascals Principle

Pressure in = Pressure out

Pressure of a liquid

P = ρgh

ρ

density (kg/m³)

g

acceleration constant (9.8 m/s²)

h

height of a liquid column (m)

Absolute pressure

P = Po + ρgh

P_o

atmosphere pressure (Pa)

Fluids

a non-solid state of matter in which the atoms and/or molecules are free to move past each other

Density

ρ = m/V

m

mass (kg)

V

volume (m³)

F_B

m_fg = ρ_fVg

Apparent weight

F_g(object)/F_B = P_o / P_f , difference in weight of an object and whatever force is pushing it upwards

Fluid Flow Continuity

A₁V₁=A₂V₂

Ideal Fluid

one that has no internal friction of viscosity and is incompressible

Fluid flow

fluids always flow from a higher pressure system to a lower pressure system

Volume

Ad

A

cross sectional areas at a point in the pipes (m²)

d

distance

Q

Av, volumetric flow rate

V (Fluid flow continuity)

Avt

Bernoulli’s Theorem

All other considerations being =, when a fluid moves faster, the pressure drops.