Materials

Question 1

Hookes Law

Answer 1

Extension is proportional to force

Question 2

Force constant

Answer 2

Force per unit extension

Question 3

Limit of proportionality

Answer 3

Materials obey Hooke’s law until this point

Question 4

Elastic limit

Answer 4

After this material will not return to original length when stress or force removed

Question 5

Elastic deformation

Answer 5

When load is removed, materials return to original length

Question 6

Plastic deformation

Answer 6

When load is removed material does not return to original length

Question 7

Tensile stress

Answer 7

Force applied over cross sectional area

Question 8

Tensile strain

Answer 8

Change in length over original length

Question 9

UTS

Answer 9

Ultimate Tensile strength

Material breaks

Question 10

Young’s Modulus

Answer 10

Stress over strain up to limit of proportionality

Question 11

Ductile Material

Answer 11

Does not lose strength when stretched
Obeys Hookes Law up to limit of proportionality, the graph curves to yield point
Material stretches without extra load

Question 12

Brittle

Answer 12

Doesn’t deform plastically
Snaps after certain point
Obeys hooks Law then stops

Question 13

Polythene

Answer 13

Behaves plastically

Question 14

Rubber

Answer 14

Elastically
Energy realised when rubber is unloaded is less than work down to stretch rubber
Does not obey Hookes law