Fluids and Solids

Question 1

density

Answer 1

how much mass it contains in a specific volume
= m/V
intensive property
kg/m^3

Question 2

specific gravity

Answer 2

density of substance compared to density of water
denisty(s)/density(w)
lighter than water
>1 –> heavier than water

Question 3

density of water

Answer 3

1000 kg/m^3

1 g/cm^3

Question 4

fluid pressure results from…

Answer 4

impulse of molecular collisions

Question 5

pressure =

Answer 5

Force/area = Pascal

Question 6

gauge pressure

Answer 6

measure of the pressure compared to local atmospheric pressure, can be negative like when suck in air to lungs or drink through straw

Question 7

for fluid at rest, P =

Answer 7

density of fluid x g x depth

Question 8

atmospheric pressure =

Answer 8

101,000 Pa

Question 9

absolute pressure

Answer 9

gauge pressure + atmospheric pressure

Question 10

Pascal’s principle

Answer 10

pressure applied anywhere to an enclosed imcompressible fluid will be distributed undiminished throughout that fluid.

Question 11

hydraulic lift equations

Answer 11

F1d1 = F2d2
F1/A1 = F2/A2

Question 12

buoyant force / Archimedes’ principle

Answer 12

buoyant force is an upward force acting on a submerged object and is equal to the weight of the fluid displaced by the submerged object
F(b) = density(fluid)*V displaced fluid *g

Question 13

uniform translational motion

Answer 13

motion of fluid as a whole, does not contribute to fluid pressure

Question 14

ideal fluids…

Answer 14

no viscosity (tendency to resist flow)
incompressible; uniform density
lacks turbulence, has steady flow
experience irrotational flow

Question 15

volume flow rate, Q

Answer 15

Q = Av
narrower pipe –> greater velocity –> decreased pressure
flow rate is constnat

Question 16

Bernoulli’s equation

Answer 16

P + densitygh + 1/2densityv^2 = K

K = constant specific to a fluid in a given situation of flow

Question 17

velocity of fluid coming from spigot =

Answer 17

v= sqrt(2gh)

Question 18

in a horizontal pipe of constant cross-sectional area, fluid will flow from high pressure to low pressure according to the equation:

Answer 18

delta(P) = QR
R = resistance to flow

Question 19

stress

Answer 19

force applied to an object divided by the area over which the force is applied
use N/m^2
stress = F/A

Question 20

strain

Answer 20

the fractional change in an object’s shape
ratio of change in dimension compared to original dimension, has no units
strain = change in dimension/original dimension

Question 21

modulus of elasticity

Answer 21

proportionality between stress and strain
= stress/strain
constant for a specific substance

Question 22

Young’s modulus

Answer 22

tensile stress, lengthening/shortening

Question 23

shear modulus

Answer 23

shear stress, tilting..

Question 24

bulk modulus

Answer 24

compression and expansion, from all sides