Materials

Question 1

Define Elastic Deformation?

Answer 1

It reforms to its original size (natural length) when force is removed

Question 2

Define Plastic Deformation?

Answer 2

When stretched it won’t return to its original size (natural length

Question 3

What is Hooke’s Law?

Answer 3

The extension is proportional to the force applied, up to the limit of proportionality

Question 4

What is Hooke’s Law as an equation?

Answer 4

F = KΔL
F = force
K = spring constant
L = extension

Question 5

On a Force-Extension graph what is the Spring Constant?

Answer 5

The gradient of the straight part of the line

Question 6

What on a Force-Extension graph indicates a material has passed the Limit of Proportionality?

Answer 6

The graph becomes a curve

Question 7

What is the area under a Force-Extension graph?

Answer 7

Energy

Question 8

What is the area between the Loading and Unloading line of a Force-Extension graph?

Answer 8

Energy lost thermaly

Question 9

What is meant by a material being Non-Hookean?

Answer 9

It does not obey Hooke’s Law

eg. Rubber

Question 10

If two springs are in Series, What happens their combined spring constant and extension?

Answer 10

They will extend twice the amount for the same force.

Their combined spring constant is half of the sum of the springs

Question 11

If two springs are in Parallel, What happens their combined spring constant and extension?

Answer 11

They will extend half the amount for the same force

Their combined spring constant is the sum of the springs

Question 12

Define Tensile Stress?

Answer 12

Force exerted per unit cross sectional area

Question 13

What is the equation for Tensile Stress?

Answer 13

σ = F/A
σ = Tensile Stress
F = Force
A = Cross Sectional Area

Question 14

Define Tensile Strain?

Answer 14

Extension per unit length

Question 15

What is the equation for Tensile Strain?

Answer 15

ε = ΔL/L
ε = Tensile Strain
ΔL = Extension (Change in length)
L = Natural Length

Question 16

What is Young Modulus?

Answer 16

The young modulus is the equivalent of the spring constant but scaled to the size and shape of the object so that it is a property of the material, rather than of a particular object

Question 17

What is the equation for the Young Modulus?

Answer 17

Young Modulus = Tensile Stress / Tensile Strain

= σ/ε = FL/AΔL

Question 18

What is the gradient of a Stress-Strain graph?

Answer 18

Young Modulus

Question 19

Define Stiff?

Answer 19

It requires a lot of force to strech it

Question 20

Define Strong?

Answer 20

It requires a lot of force to break it

Question 21

Define Brittle?

Answer 21

It breaks without much plastic deformation

Question 22

Define Ductile?

Answer 22

It can survive a lo of plastic deformation

allows it to be pulled in to thin wires

Question 23

Define Malleable?

Answer 23

It can be beaten into shape

Question 24

Define Hard?

Answer 24

The surface cannot be easily scratched

Question 25

Define Tough?

Answer 25

It will absorb a lot of energy before breaking

Question 26

What is the equation for Density?

Answer 26

ρ = m/V
ρ = Density
m = Mass
V = Volume

Question 27

What is the equation for Elastic Potential Energy using Spring Constant?

Answer 27

E = 0.5 x K (ΔL)²
E = Energy
K = Spring Constant
ΔL = Extension

Question 28

What is the equation for Elastic Potential Energy using Force?

Answer 28

E = 0.5 FΔL
E = Energy
F = Force
ΔL = Extension