Chapter 15 - Fluids Flashcards
what are the intermolecular bonds like in solids
strong
what are the intermolecular bonds like in liquids
weak
what are the intermolecular bonds like in gases
negligible
what does the average direction of the force on a surface = and why
the force perpendicular to the surface because the tangential components tend to cancel out
is pressure scalar or vector
scalar
is force scalar or vector
vector
what is pascals law
any additional pressure applied to an enclosed fluid is transmitted undiminished to all parts of the fluid and the enclosing walls
does pressure in a uniform static fluid depend on height
yes
does pressure in a uniform static fluid depend on shape of vessel
no
where is pressure constant
for all points along a horizontal surface on or in the fluid
how many atm in 10m of water
1atm
how many atm in 100m of water
10atm
how many atm in 1m of water
0.1atm
what do gauge pressures measure
the difference between ambient atmospheric pressure and the unknown pressure
(Ptot-Po)
which direction does the buoyant form point
upwards against gravity
what is Archimedes principle
magnitude of buoyant force = weight of fluid displaced by object
what are 3 key points of Archimedes principle
1-true for object of any shape
2-true for fully or partially submerged objects
3-true for objects simultaneously immersed in more than one fluid
what are our 3 assumptions that we made in fluid dynamics
1- ideal fluid
2-laminar flow
3-steady state flow
what is an ideal fluid
non-viscous and non-compressible
what is laminar flow
no turbulence
what is steady-state flow
flow characteristics are constant over time (speed, pressure…)
what does the continuity equation say
that, for a steady-state flow of an ideal fluid, the volume flow rate is constant throughout the flow system
what is constant in the continuity equation
the volume flow rate
what does an increase in fluid speed get accompanied by
drop in pressure
what is a counterintuitive thing that happens in the Bernoulli effect
an increase in fluid speed gets accompanied by a drop in pressure
what are 2 main assumptions with the Bernoulli effect
1-when fluid is open to air, P=Po
2-when flowing from a large pipe to a small one, if A1<
what is viscosity
measure of resistance to flow
what causes viscosity (2)
friction between flowing fluid and container wall and friction between adjacent fluid layers
what must you assume in the Bernoulli equation
that there is zero viscocity
which law do we use if the viscosity is specified
Poiseuille
which 2 things are we going to assume are always true
steady-state and continuity equation
