Materials Vocabulary sheet for chapter 4

Question 1

What are the units of stress?

Answer 1

Nm^-2 or Pa

Question 2

What is the equation for stress?

Answer 2

Force
______
area

Question 3

What are the several types of stress?

Answer 3

Tension(stretching),compression,torsion(twisting)

Question 4

Unit for strength?

Answer 4

Pa

Question 5

What is the definition for strong?

Answer 5

A large stress is needed to cause failure.

Question 6

What is the definition for strength?

Answer 6

The maximum stress a material can withstand before failure.

Question 7

What is the definition for weak?

Answer 7

Little stress needed to cause failure.

Question 8

What are the units for toughness?

Answer 8

J/m^2

Question 9

What is toughness?

Answer 9

1) Needs a large amount of energy to break it.
2) Undergoes a large amount of plastic deformation before breaking.
3) Resists crack propagation.

Question 10

What is toughness defined as strictly?

Answer 10

1) The energy required to create a new surface area,units are J/m^2
2) The energy absorbed per unit volume,units are j/m^3

Question 11

What is a brittle materials?

Answer 11

Does not undergo much plastic deformation, the break soon after elastic limit.
2)Cracks pass easily through the material and fracture tends to be sudden and catastrophic.

However,brittle materials can strong.

Question 12

What are hard materials?

Answer 12

Materials that are resistive to dents or scratches.Units are Pa

Question 13

What is the definition of elastic?

Answer 13

Changes shape when stress is applied but returns to its original shape when stress removed.

Question 14

What is the definition of plastic?

Answer 14

Does not return to its original shape after deformation.

Plastic deformation is a permanent change of shape.

Question 15

What is meant by ductile?

Answer 15

Can be easily drawn into a wire.

Question 16

What is meant by malleable?

Answer 16

Can easily be hammered or pressed into shape.