4. Fluids Formulas (10%)

Density

• variables: mass, volume

Density of Water (2)

Force of Gravity Applied to an Object/Weight of a Volume of Fluid (aka the “force down” applied onto an object submerged in a fluid and is directly opposed by buoyant force)

• variables: density of object/fluid, volume of object/fluid

(density of liquid or object / density of water)

Specific Gravity (% of an object that is submerged in water)

• if SG > 1, object will sink

Pressure

• variables: normal force, area

Pressure units

Absolute Pressure

• variables: ambient/surface pressure, fluid density, depth of object

Gauge Pressure

• variables: absolute pressure, atmospheric pressure

Pascal’s Principle (2)

(remember volume = area x height)

Buoyant Force // Upward Force Applied to a Submerged Object as Exerted by the Fluid (which opposes the object’s weight, causing it to float/rise) (aka the “force up” applied onto an object submerged in a fluid and is directly opposed by the force of gravity)

• variables: fluid density, volume of fluid displaced/submerged

Critical Velocity/Speed [the flow speed at which the fluid's movement transitions from smooth, orderly (laminar) flow to chaotic, irregular (turbulent) flow]

• variables: fluid viscosity, fluid density, diameter of the tube

Continuity Equation // Flow Rate/Flux

• variables: velocity at 2 points, cross-sectional areas at 2 points

(essentially PE₁ + KE₁ = PE₂ + KE₂ except you add pressure and replace mass with density)

Bernoulli’s Equation