* remember that density changes with compression because volume will change
Specific Gravity
Makes density more intuitive
SG = ρ_{substance} / ρ_{water}
ρwater: 1 g/cm^{3} or 1000 kg/m^{3 }
Pressure
P = F / A
when an object is submerged: pressure is equal to the force felt on the object divided by the surface area
* remember that pressure is there regardless of if the object is, this just makes it more intuitive
Fluids at Rest
Fluids are at rest when they are only experiencing a force perpendicular to its surface
P = ρgy
* remember that if the container is open you must add P_{atmos} which is 101 000 Pa
Pascal's Principal
Pressure applied to an incompressable fluid will be evenly distributed
a hydrolic lift utilizes this principal (F applied to smaller S.A. --> P trans --> since the larger S.A. is larger the F is greater on it (no change in work though so the distance is less)
Archimedes Principal
an object submerged in water displaces a volume of fluid equal to its own volume
an object floating displaces a volume of fluid equal to its weight
Buoyancy Force
Submerged: F_{b} = ρ_{fluid} V g
Floating: F_{b} = mg_{obj} = mg_{fluid}
Fraction Submerged: ρ_{obj} / ρ_{fluid}
Center of Buoyancy
is the point were the center of mass would be if the object were uniformly dense
the actual center of the object
Fluids in Motion - Types of Motion
1) Random Translational - contributes to fluid pressure as in a fluid at rest
2) Uniform Translational - shared by molecules at a given location
energy from these two types of motion can be converted back and forth
How do real fluids compare to ideal fluids?
real have drag, viscocity
drag works at the fluid-object interface, therefore the greatest velocity will be at the point farthest from that interface
Flow Rate
Q = A v
Q: volume flow rate
A: area
v: velocity
Bernoulli's Equation
P + ρgh + 0.5ρv^{2} = K
the sum of these three terms is a constant at any point in the fluid
term 1: pressure
term 2: potential
term 3: kinetic
As velocity increases, pressure
decreases
think of the bee swarm standing vs. running analogy
Surface Tension
temp dependent - the higher the temp the weaker the surface tension
if the adhesive forces (to the container) are stronger than the cohesive forces (between molecules) the miniscus will be a 'U' shape