Material

Question 1

equation for density

Answer 1

Density(p)=mass(m)/Volume(v)

Question 2

equation for upthrust

Answer 2

Upthrust= Density of fluid x volume x gravity

Question 3

Unit for denisty

Answer 3

kg/m^3 (kgm^-3)

Question 4

How to use a vernier Caliper

Answer 4

1)close the jaws and check for zero error. Zero error has to be accounted for in end result.
2)At zero mark, the reading of the main scale
3) the vernier scale with the main scale
4) add together and take account for zero error

Question 5

Accuracy

Answer 5

how close you are to the true value

Question 6

sensitivity

Answer 6

how small a division a piece of equipment can measure to

Question 7

precision

Answer 7

how similar repeated values are

Question 8

measuring density of irregular objects

Answer 8

1)measure mass with a top pan balance
2)measuring the volume with a displacement can/measuring cylinder

Question 9

Liquid densities

Answer 9

1cm^3 = 1ml
tap water = 1gcm^-3 =1000kgm^-3

Question 10

Upthrust definition

Answer 10

upthrust is the upward force on an object from the material it is in

Question 11

Archimedes principle

Answer 11

Upthrust is the same as weight of material displaced

Question 12

upthrust equation

Answer 12

density of fluid (pf) x volume of fluid displaced(vf) x accel due to gravity(g)

Question 13

if an object is floating and no movement

Answer 13

Upthrust of fluid = weight of object
pfvfg=povog
pfvf=movo

Question 14

if object is floating on the surface is partially submerged

Answer 14

density of fluid > denisty of object
Uf=Wo

Question 15

if object is fully submerged

Answer 15

volume is the same therefore the densities of the submerged object and material around is the same.
pf=po

Question 16

what is terminal velocity?

Answer 16

Terminal velocity is the constant velocity that is reached when Upthrust + viscous drag = weight
RF=0

Question 17

Free body diagram of falling

Answer 17

^ Force due to drag
I
I Upthrust+Drag=weight
O
I ^
I I upthrust
I
v Weight

Question 18

Free body diagram of rising

Answer 18

^ upthrust
I
I
I Upthrust=Drag+weight
O
I I Drag
I v
v Weight

Question 19

Equation for stokes law

Answer 19

to calculate viscous drag

F=6xpixradiusxviscosityxv

Question 20

Conditions for stokes law

Answer 20

• Small
• Spherical object
• low speed
• laminar flow

Question 21

CPAC 4-

Answer 21

1) Drop a ball bearing of known density and diameter through washing up liquid of unknown viscocity
2) Record distance and times between three markers as shown using the split time function. Determine terminal velocity
3) Repeat each ball multiple times to get more accurate results
4) At terminal velocity , Weight = Drag + upthrust
5)Drag=Weight - upthrust
6pinrv=4/3pir^3Pirong-4/3pir^3Pliquidg
this equates to

n= 2r^2g(Piron-Pliquid)
—————————–
9v

Question 22

laminar flow definition

Answer 22

Laminar flow is a type of airflow around an object that is smooth and consistent, with a minimum of disturbance and separation

Question 23

Turbulent flow definition

Answer 23

Turbulent flow is a type of fluid flow in which the fluid undergoes irregular fluctuations, or mixing

Question 24

equation for volume of
a) cuboid
b) sphere
C) cylinder

Answer 24

a) basexheightxdepth
b)4/3pir^3
C)pir^2xdepth

Question 25

state weight in terms of density

Answer 25

weight = density x volume x gravitational field strength

Question 26

what is the equation for work done in limit of proportionality

Answer 26

workdone = 0.5 x force x extention (this is always = amount of elastic potential energy stored)

Question 27

what is the equation for work done out limit of proportionality

Answer 27

workdone = 0.5 x stiffness x extention^2

Question 28

Force extention graph gradeint =

Answer 28

n/m (newton metre)

Question 29

stress equation

Answer 29

Force(n)/Area(m^2)

Question 30

Define density

Answer 30

The mass per unit of volume

Question 31

Define Upthrust

Answer 31

Upthrust, or buoyancy, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object

Question 32

Viscous drag

Answer 32

Viscous drag is a force of friction that is present when a solid object moves through a fluid

Question 33

define stress

Answer 33

Force per unit area

Question 34

define strain

Answer 34

strain refers to the relative deformation or change in shape and size of elastic, plastic, and fluid materials under applied forces.

Question 35

Young modulus experiment

Answer 35

1.Measure the diameter of the wire with a micrometre screw gauge or digital callipers. Take at least 3 readings and find an average
2.set up the apparatus so the wire is taut. No masses should be on the mass hanger just yet
3.Measure the original length of the wire using a metre ruler and mark a reference point with tape preferably near the beginning of the scale eg. at 1 cm
4.Record initial reading on the ruler of the reference point
5.Add a 100 g mass onto the mass hanger
6.Read and record the new reading of the tape marker from the meter ruler
7.Repeat this method by adding a 100 g mass (at least 5 – 10 times) and record the new scale reading from the metre ruler

Question 36

define strength

Answer 36

Strength is a measure of the stress that can be applied to a material before it permanently deforms or breaks

Question 37

ultimate tensile strength

Answer 37

The maximum stress reached before fracture

Question 38

define tough

Answer 38

The ability to absorb energy and plastically deform without fracture

Question 39

define ductile

Answer 39

materials that can be stretched or bent without breaking under stress

Question 40

define brittle

Answer 40

materials that are easily broken, cracked, or snapped when subjected to stress. Brittle materials have little or no plastic deformation

Question 41

equation for young modulus

Answer 41

young (nm^-2)=Stress(nm^-2)/strain

Question 42

derived young modulus formula

Answer 42

young= force x original length / area x extension

Question 43

define young modulus

Answer 43

Young’s modulus is a measure of how stiff a material is when it is stretched or compressed

Question 44

limit of proportionality

Answer 44

The limit of proportionality is a term that describes the point at which the extension of an elastic object, such as a spring, is no longer directly proportional to the force applied to it. This means that Hooke’s law, which states that force is equal to the spring constant times the extension, is no longer valid beyond this point.

Question 45

yield point

Answer 45

The yield point is a term that describes the moment when a material stops deforming elastically and instead begins to plastically deform.

Question 46

what is plastic deformation

Answer 46

Plastic deformation is the process in which an object changes its size or shape in a way that is not reversible because of the applied force

Question 47

elastic deformation

Answer 47

Elastic deformation is a temporary change in the shape or size of a material that occurs when the applied stress is less than the elastic limit of the material

Question 48

elastic limit

Answer 48

the elastic limit is the maximum amount of stress that can be applied to a material before the onset of plastic deformation

Question 49

explain the link between stress, strain and young modulus

Answer 49

Stress is the force per unit area acting on a material. It can be tensile, compressive, or shear, depending on the direction of the force. Strain is the change in length per original length of a material. It can be positive (elongation) or negative (contraction). Young modulus is the ratio of stress and strain for a material in the elastic region. It is a measure of how stiff a material is, or how much it resists deformation.

The relationship between stress and strain is linear for a material in the elastic region, which means that they are directly proportional to each other. This is expressed by Hooke’s law, which states that stress is equal to Young modulus times strain