Chapter 6 - Materials

Question 1

how does extension take place

Answer 1

through tensile forces acting away from the object in both directions

Question 2

how does compression occur

Answer 2

tensile forces going towards the centre of an object in both directions

Question 3

Hooke’s law principle

Answer 3

force applied is directly proportional to the extension of an object, up to the limit of proportionality

Question 4

tensile stress

Answer 4

force per unit area

Question 5

tensile strain

Answer 5

extension / original length

Question 6

how is energy stored during elastic deformation

Answer 6

work done is transferred and stored as elastic potential energy

Question 7

energy changes which occur during plastic deformation

Answer 7

material is stretched and the energy from the work done is used to break bonds between molecules, causing permanent deformation

Question 8

breaking stress

Answer 8

amount of stress a material can withstand without breaking

Question 9

brittle material definition

Answer 9

doesn’t extend much when a force is applied. material tends to break instead.

Question 10

what does the area under a force-extension graph represent

Answer 10

the energy stored in a material

Question 11

Youngs modulus

Answer 11

tensile stress / tensile strain