5 - Fluids and Solids Flashcards
Fluid=
is liquid or gas. Constantly breaking and reforming bonds due to high kinetic energy. -conforms to the shape of its container.
Density=
is the ‘heaviness’ of a fluid, it is how much mass it contains in a specified volume (V).
** p= m/V
S.G.= p (substance)/ p (water)
p (water)= 1000 kg/m^3 p (water)= 1 gm/cm^3**
fluid pressure=
the average magnitude of the force, and divide it by the area over which the collisions are taking place (surface area) we have the pressure experienced by the object.-results from impulse of molecular collisions.
- P = F/A**
- S.I. unit of pressure is the Pascal (Pa)
-for fluid at rest with uniform density in a sealed container, pressure:
P = pgy
P (atmospheric)= 101,000 Pa
gauge pressure=
is a measure of the pressure compared to local atmospheric pressure.
Pascal’s principle=
Hydraulic lift=
Buoyant force=
each point in an enclosed fluid must bear any increase in pressure.
is a simple machine which works Pascal’s principle.
upward force acting on a submerged object, and is equal to the weight of the fluid displaced by the submerged object.
** Fb= p (fluid) VG**
*fully submerged object displaces its volume in fluid, floating object displaces its weight in fluid.
P (abs((absolute pressure))) = P (gauge) + P (atmospheric)
Random translational motion=
Uniform translational motion=
that contributes to fluid pressure as in a fluid at rest.
shared equally by all the molecules at a given location in a fluid.
Ideal fluids–>
1) no viscosity, or its tendency to resist flow.
2) incompressible, it has uniform density.
3) lacks turbulence or experiences steady flow.
4) Will not rotate about its axis as it flows.
Continuity=
Q = Av
Q–> volume flow rate
I = pQ = pAv
*in an ideal fluid, flow rate is constant.
Bernoulli’s Equation=
P + pgh + 1/2pv2 = K
Non-ideal=
all real fluids are non-ideal.
(delta) P= QR
Surface tension=
Intermolecular forces=
is the intensity of the intermolecular forces per unit length.
pull inward tending to minimize the surface area by creating a more spherical shape.
Stress=
is the force applied to an object divided by the area over which the force is applied.
** Stress = F/A**
Strain=
is the fractional change in an object’s shape. Strain is a ratio of change is dimension compared to original dimension, and has no units.
Strain= (delta) dimension
Original dimension
*Stress is what is done to an object, and strain is how the object responds.
Modulus of elasticity=
the proportionality of stress and strain.
Modulus of elasticity= stress
Strain
Young’s modulus=
Shear Modulus=
Bulk modulus=
(E ) for tensile stress
(G) for shear stress
(B) for compression and expansion
