Materials

Question 1

Force extension graph

Answer 1

X=extension
Y=force
M=stiffness
A=Elastic strain energy

Question 2

What is the unit for stress?

Answer 2

Pascals

Question 3

Stress strain graph

Answer 3

X=strain
Y=stress
M=young modulus

Question 4

Determing youngs modulus of a wire

Answer 4

Measure original length of wire from fixed end to a marker
Measure diameter with micrometer and calculate CSA
Use incrementally heavier masses to increase force on wire
Record extension of the wire
Calculate stress and strain
Plot on graph
Calculate gradient

Question 5

Elastic

Answer 5

Material returns to original size and shape when force is removed

Question 6

Plastic

Answer 6

Material remains permanently deformed

Question 7

Brittle

Answer 7

Material fractures before any plastic deformation takes place

Question 8

Limit of proportionality

Answer 8

Point after which the material no longer obeys hookes law

Question 9

Elastic limit

Answer 9

Point after which material stops behaving elastically and starts behaving plastically

Question 10

Breaking stress

Answer 10

Value of stress when the material breaks

Question 11

Maximum tensile stress

Answer 11

The maximum stress a material can withstand