C6

Question 1

Describing a stress-strain graph (3)

Answer 1

elastic OR plastic
does OR does not obey Hooke’s law
Loading / unloading graphs same OR different

Question 2

When doing Young Modulus calculations what should you do?

Answer 2

Show calculations of stress and strain individually

Question 3

Hooke’s Law (1)

Answer 3

extension is directly proportional to force (applies as long as elastic limit is not exceeded)

Question 4

Plastic deformation (1)

Answer 4

material does not return to original length / shape/ size when force is removed

Question 5

Young Modulus (2)

Answer 5

stress/strain (stress divided by strain)

as long as elastic limit is not exceed / in linear region of stress strain graph / Hooke’s law is obeyed

Question 6

Young Modulus PAG (8)

Answer 6

MEASUREMENTS: original length, final length + extension, weight

EQUIPMENT: ruler, scales to measure mass, micrometer for diameter –> area

Determining YM: stress = force / cross sectional area
strain = extension / original length

YM = stress / strain

Question 7

Force constant (1)

Answer 7

force/ extension

OR force per unit extension