6. Fluids & Solids

Question 1

what are the 2 things that can be a fluid

Answer 1

gas or liquid

Question 2

what is the molecular arrangement like in fluids and how do they move

Answer 2

not arranged in any order/structure and thus move in random directions relative to each other

Question 3

what is density

Answer 3

amount of mass a fluid contains in a specific volume

Question 4

what is the equation for density

Answer 4

p = m/V

Question 5

what is the unit for density

Answer 5

g/cm^3

kg/m^3

Question 6

put the following into order from greatest to least density

Answer 6

solid > liquid > gas

Question 7

what does being least dense mean for gas

Answer 7

it can be compressed

Question 8

are solids and liquids compressible in terms of the GAMSAT

Answer 8

no

Question 9

what is specific gravity

Answer 9

ratio of density of substance to density of water

Question 10

what is the equation for the specific gravity

Answer 10

SG = p(substance)/p(water)

p = density

Question 11

if we want to calculate the specific gravity and the density is not known what do we do

Answer 11

use weight or mass of substance to find specific gravity

specific gravity will still be the same

Question 12

what is the density of water

Answer 12

1g.ml = 1g/cm^3

same as 10^3kg/m^2

Question 13

what does it mean relative to water if the specific gravity is less than one

Answer 13

substance is lighter than water

Question 14

what does it mean relative to water if the specific gravity is less than one

Answer 14

substance is lighter than water

Question 15

what does it mean relative to water if the specific gravity is more than one

Answer 15

substance is heavier than water

Question 16

what does it mean relative to water if the specific gravity is equal to one

Answer 16

substance equally as heavy as water

Question 17

what is the equation for pressure

Answer 17

P = F/A

F = perpendicular force to area in Newtons
P = pressure in pascal (1Pa = 1N/m^2)

Question 18

what is pressure defined as

Answer 18

potential energy per unit volume

Question 19

what is the equation for calculating pressure

Answer 19

P = pgh

p = density of gas or fluid (kg/m^3)
g = acceleration due to gravity (9.80m/s^2)
h = height of a column of gas or fluid (m)

Question 20

at a certain depth what is known about the pressure of the fluid

Answer 20

it is the same in all directions

Question 21

does the shape or surface area of the container affect fluid pressure

Answer 21

no

Question 22

fluids exert forces that are always 90 degrees to what

Answer 22

to the surface of the container

Question 23

the pressure of a fluid is directly proportional to what 2 characteristics of the fluid

Answer 23

its density and its depth

Question 24

what is the buoyant force

Answer 24

when object is submerged in water the upward force that acts on submerged object is the buoyant force

Question 25

what is achimedes principle

Answer 25

buoyant force is upward force that acts on submerged object and equal to weight of fluid that is displaced by the submerged object

Question 26

what is the unit of pressure

Answer 26

Pascals (Pa)

Question 27

what is the equation for buoyant force

Answer 27

Fb = p(fluid)Vg

Question 28

the specific gravity of the fluid is equivalent to what characteristics of the object

Answer 28

the height of an object partially submerged in the fluid

Question 29

what is laminar flow in terms of particle movement direction and rate

Answer 29

all particles in fluid are moving in straight line in the same direction moving at the same rate

Question 30

what is turbulent flow in terms of particle movement direction and rate

Answer 30

irregular flow of particles move in a state of chaos some particles oppose the direction of others and cause collisions

Question 31

what is the equation for calculating the rate of laminar flow through a pipe

Answer 31

Volume = cross sectional area x distance Distance = velocity x time so Volume = cross sectional area x velocity x time (V = Avt) Rate = volume past a point/time R = Avt/t R = Av

Question 32

what is the continuity equation

Answer 32

A1V1 = A2V2 A = cross sectional area V = flow velocity

Question 33

what is fluid velocity

Answer 33

resistance of fluid layers to flow past each other

Question 34

what is the relatioship between velocity and speed

Answer 34

high velocity = slower

Question 35

what is reynolds number used to determine

Answer 35

whether the flow of a fluid is laminar or turbulent

Question 36

what is the equation for calculating reynolds number

Answer 36

R = vdp/n d = diametre of tube n = viscosity coefficient

Question 37

what does it mean if reynolds number is <2000

Answer 37

flow in a pipe is generally laminar

Question 38

what does it mean if reynolds number is >2000

Answer 38

flow is generally turbulent

Question 39

what is surface tension

Answer 39

intensity of intermolecular forces per unit length

Question 40

what does surface tension adirse from

Answer 40

an imbalance of the cohesive forces between molecules

Question 41

which is the imbalance of the cohesive forces between molecules that surface tension arise from regarding molecules in bulk liquid

Answer 41

molecule in bulk liquid experiences cohesive forces with other molecules in all directions

Question 42

which is the imbalance of the cohesive forces between molecules that surface tension arise from regarding molecules at the surface of liquid

Answer 42

molecule at surface of liquid experiences only net inward cohesive forces

Question 43

what are the 2 components of elasticity in solids

Answer 43

stress strain

Question 44

what is stress in terms of elasticity for solids

Answer 44

ratio of force applied to object on area over which the force is applied

Question 45

what is the unit for stress

Answer 45

N/m^2

Question 46

what is strain defined as in terms of elasticity for solids

Answer 46

fractional change in dimension of object caused by stress

Question 47

what is the unit of strain

Answer 47

it has no units

Question 48

what is the relationship between stress and strain

Answer 48

proportional to each other

Question 49

what is the modulus of elasticity

Answer 49

stress and strain are proportional and is given as a ratio

Question 50

what is the equation for modulus of elasticity

Answer 50

ME = stress/strain