Chapter 12 - The Technological World

Question 1

What is a constraint?

Answer 1

The effect an external force has on a certain material

Question 2

What are the five types of constraints?

Answer 2

Compression, tension, torsion, shearing, deflection.

Question 3

What is compression? (description, symbol, example)

Answer 3

1. Description: crushing
2. Symbol: —–> <—–
3. Example: Hands squeezing a wet sponge

Question 4

What is deflection? (description, symbol, example)

Answer 4

1. Description: Bending
2. Symbol: |î|
3. Example: A fish bending a finishing rod

Question 5

What is tension? (description, symbol, example)

Answer 5

1. Description: Stretching
2. Symbol: <—- —->
3. Example: rope in a tug of war

Question 6

What is torsion? (description, symbol, example)

Answer 6

1. Description: Twisting
2. Symbol: rotating
3. Example: wringing out a towel

Question 7

What is shearing? (description, symbol, example)

Answer 7

1. Description: Cutting
2. Symbol: —-> | ⇽—-
3. Example: Scissors cutting paper

Question 8

What are the three types of deformations?

Answer 8

1. Elastic
2. Plastic.
3. Fracture

Question 9

What is an elastic type of deformation?

Answer 9

Temporary change in shape or dimensions of the material. Material will automatically return to its original form.

Question 10

What is a plastic type of deformation?

Answer 10

Permanent change in the shape or dimensions, material remains deformed.

Question 11

What is a fracture type of deformation?

Answer 11

Material Breaks.

Question 12

What are the six Mechanical Properties of Materials?

Answer 12

1. Hardness
2. Elasticity
3. Resilience
4. Ductility
5. Malleability
6. Stiffness

Question 13

What is the mechanical property of hardness?

Answer 13

Ability to resist indentation/scratches

Question 14

What is Elasticity?

Answer 14

Ability to return to their original shape after undergoing a constraint.

Question 15

What is resilience?

Answer 15

Ability to resist shocks without breaking

Question 16

What is ductility?

Answer 16

Ability to be stretched without breaking

Question 17

What is malleability?

Answer 17

Ability to be flattened or bent without breaking

Question 18

What is stiffness?

Answer 18

Ability to retain their shapes when subjected to various constraints.

Question 19

What are the three other properties of mechanical materials?

Answer 19

1. Resistance to corrosion
2. Electrical conductivity
3. Thermal conductivity

Question 20

What is resistance to corrosion?

Answer 20

Ability to resist the formation of rust or
degradation by acids, salt, water, etc.

Question 21

What is electrical conductivity?

Answer 21

Ability to carry and electrical current

Question 22

What is thermal conductivity?

Answer 22

Ability to transmit heat

Question 23

What is degradation?

Answer 23

Decline in a material’s properties due to the effects of the surrounding environment.

Question 24

What is protection of a material?

Answer 24

Application of a substance to a material to prevent or delay its degradation.

Question 25

What are the 2 categories of wood, where do they come from?

Answer 25

1. Hardwood → Deciduous trees 2. Softwood → Conifers

Question 26

What is modeified wood?

Answer 26

Wood mixed with other substances (glue, plastics, preservatives)

Question 27

What are three problems with wood?

Answer 27

1. Rotting 2. Infestation 3. Mold

Question 28

What are two solutions to the problems caused when using wood?

Answer 28

1. Coating 2. Treated wood

Question 29

What are problems with ceramics?

Answer 29

1. Acids and bases can degrade ceramics 2. A sudden change in temperature can deteriorate the properties of ceramic

Question 30

What are problems with metals and alloys?

Answer 30

1. They rust

Question 31

What is the solutions to the problems of metals and alloys?

Answer 31

1. Coating!!

Question 32

What are plastics made out of?

Answer 32

Fossil fules

Question 33

What is a thermoplastic?

Answer 33

Become soft when heated and hard when cooled (can be recycled)

Question 34

What is a thermosetting plastic?

Answer 34

Remains permanently hard when heated (more resilient)

Question 35

What are the three problems for plastic degradation?

Answer 35

1. Water absorbsion 2. Oxidation 3. Uv rays

Question 36

What are the three solutions to the problems regarding plastics?

Answer 36

1. Waterproof coating 2. Antioxidant material 3. pigment to absorb UV ray

Question 37

What are the two combination of materials used for composites?

Answer 37

1. Reinforcement (provides strength) 2. Matrix (surrounds and supports the reinforcement)