11- materials

Question 1

what is density

Answer 1

mass per unit volume

Question 2

density calculation

Answer 2

p= m/v

Question 3

what is hookes law

Answer 3

• the force required to produce an extension is directly proportional to the extension up to the limit of proportionality

Question 4

hookes law equation

Answer 4

F= K △L

Question 5

What is the gradient of the straight line in force extension graphs?

Answer 5

the spring constant of the material

Question 6

what is the end of the straight line region in a force extension graph?

Answer 6

the limit of proportionality

Question 7

what is the area under the graph in a force extension graph

Answer 7

work done in the stretching of the material

Question 8

what is the work done formula

Answer 8

w= F △l/2

Question 9

how do you convert a mass to a force

Answer 9

F = mg

Question 10

what happens to springs in parallel when an object is hung from them

Answer 10

they will both extend by the same amount regardless of spring constants

Question 11

what’s the force acting on springs in parallel like

Answer 11

both/ all springs will experience a different force (unless identical spring constants)

Question 12

what is the equation for weight in springs in parallel

Answer 12

w= (k1 + k2) △l

Question 13

what is the equation for total spring constant for springs in parallel

Answer 13

k= k1 + k2

Question 14

what happens to springs in series when an object is hung from them

Answer 14

both springs will support the load but will extend by different amounts (unless identical spring constants)

Question 15

what’s the force in spring in series like

Answer 15

due to newtons 3rd law, there is an equal but opposite force

Question 16

what is the equation for weight in springs in parallel

Answer 16

F1= K1 △l1
F2= K2 △l2

Question 17

what is the equation for total spring constant in springs in series

Answer 17

1/K = 1/K1 + 1/K2

Question 18

what does it mean when an object displays plastic behavior

Answer 18

it means a force has been applied to an object but once removed the object did not return to its original shape

Question 19

what is tensile stress

Answer 19

the force per unit cross-sectional area

Question 20

what is the equation for tensile stress

Answer 20

stress= F/A

Question 21

what is tensile strain

Answer 21

the strain experienced by an object is the ratio of the extension to its original length

Question 22

tensile strain equation

Answer 22

Ɛ = ΔL / Lo

Question 23

what is young modulus

Answer 23

the ratio of stress over strain for a material. it is a measure of a solids stiffness

Question 24

what is the young modulus equation

Answer 24

E= FL / A ΔL

Question 25

what are brittle materials

Answer 25

materials which break easily, and have little of no plastic deformation

Question 26

what is an example of an elastomer

Answer 26

rubber bands

Question 27

what is the work done in an elastomer stress-strain graph

Answer 27

it is the area under the loading graph

Question 28

what is the work done when a rubber band is returning to its original shape in an elastomer stress-strain graph

Answer 28

the area under the unloading graph