Science chapter 12

Question 1

What are the five constraints?

Answer 1

1) compression
2) tension
3) torsion
4) deflection
5) shearing

Question 2

What are 3 types of deformations, what is the description of each?

Answer 2

1) elastic; temporary change in material
2) permanent change (hole, dent)
3) Fracture; so intense it breaks

Question 3

What are the 6 Mechanical properties, what is the property?

Answer 3

1) hardness; ability to resist indentation or abrasion
2) elasticity; ability to return to the original shape after a constraint
3) resilience; ability to resist shock
4) ductility; ability to be stretched
5) malleability; ability to flattened, or bent
6) stiffness; ability to keep the same shape

Question 4

What are the 3 other properties

Answer 4

1) resistance to corrosion: doesn’t rust quickly
2) electrical conductivity; can carry an electrical current
3) thermal conductivity; ability to transmit heat.

Question 5

What are the properties of wood?

Answer 5

• hardness, elasticity, resilience, toughness (resistance to fracture)
  -low thermal conductivity
  -easy to shape and assemble
• different colours and shapes
  -lightness

Question 6

What is modified wood?

Answer 6

A treated wood, or a material made from wood mixed with other substances

Question 7

What makes wood degrade?

Answer 7

-rotting
-fungi
-microorganisms
-insects
-water

Question 8

how do you protect wood?

Answer 8

putting a protective coating, treating it (alkaline solution containing copper,or heat treating it).

Question 9

Properties of Ceramics

Answer 9

• low electrical conductivity
  -high degree of hardness
  -resistant to corrosion
  -can be fragile or resilient

Question 10

Degradation of ceramics and how to protect it?

Answer 10

-when exposed to stronger acids then bases
-Baking process

Question 11

Properties of metals and alloys?

Answer 11

-good conductors of heat
-good conductors of energy
-malleability
- ductility

Question 12

How do metals and alloys degrade? How do you fix it?

Answer 12

-oxidation
-metallic coverings (zinc, chrome)
-other coatings (paint, grease)
-Heat treatments (quench hardening and tempering)

Question 13

What are plastics made of?

Answer 13

made from polymers, developed mainly from patrolium (oil) and natural gas, to which other substances may be added to get certain properties.

Question 14

What is a thermoplastic?

Answer 14

A plastic that becomes soft enough when heated to be moulded or remoulded and hardens enough when cooled too hold it’s shape.

Question 15

What is a thermosetting plastic

Answer 15

A plastic that remains permanently hard even when heated - cannot be reshaped

Question 16

What is the cause for degradation in plastics? and what is the solution

Answer 16

-penetration by a liquid (water proof coating)
-oxidation ( adding antioxidants (carbon black))
-ultraviolet rays (adding pigments that absorb light)

Question 17

what is a composite?

Answer 17

formed by combining materials from different categories to obtain materials with enhanced properties.
1) the matrix skeleton
2) he reinforcements

Question 18

What degrades a composite?

Answer 18

-fracture of the matrix or the reinforcements
-loss of adherence between the matrix and the reinforcement
Protection: choose materials that aren’t likely to deform or break.

Question 19

What are the two types of projections?

Answer 19

1) isometric
2) multiview

Question 20

what is an advantage of the isometric projection?

Answer 20

all three dimensions in a single view (length, width, height)

Question 21

what is an advantage of multi-view projection?

Answer 21

provides greater detail without distortion

Question 22

What is a general arrangement drawing?

Answer 22

a technical drawing representing the overall appearance of an object. (usually drawn to scale)

Question 23

what is an exploded view drawing?

Answer 23

a drawing where various parts of an object are shown separated from each other

Question 24

what is a detailed drawing?

Answer 24

a drawing specifying all the relative information for manufacturing a part

Question 25

Dimensional tolerance is?

Answer 25

an indicator of the maximum acceptable difference between a specified measurement and the actual on the finish object.

Question 26

Functional dimension is?

Answer 26

drawing that specifies the information needed for the object to work.

Question 27

Development is?

Answer 27

the net of the object.

Question 28

What are the 3 types of diagrams?

Answer 28

1) design plan
2) Technical diagram
3) Circuit diagram

Question 29

What is the purpose of a design plan and what information is conveyed?

Answer 29

Purpose; provides information on one or more of the operating principles of an object
Information;
1) names of parts
2) Movement of the parts
3) Operational forces involved
4) any other useful information for understanding how the object works

Question 30

What is the purpose of a Technical diagram and what information is conveyed?

Answer 30

Purpose; provides information on the selected manufacturing process of an operational object
Information;
1) Important shapes and dimensions to be considered in the manufacturing or parts
2) Names of parts
3) Materials to be used
4) Linking components, if applicable
5) Types of guiding controls, if applicable

Question 31

What is a circuit diagrams purpose and what information does it convey?

Answer 31

purpose; provides information on the layout of various components of an electrical circuit
information;
1) various circuit components
2) any other useful information for understanding how the electrical should be built.

Question 32

What are the two categories of tools?

Answer 32

Hand tools; hand saw, screwdriver, hammer
Machine tools; drill, jigsaw

Question 33

What are the 5 techniques of the Machining of parts?

Answer 33

1) cutting; giving a materials its desired shape; using different types of tools
2) drilling; making a hole in the material; usually with a bit on the hand drill or an electric drill.
3) Tapping; a machining techniques where a screw threads are formed inside holes drilled into materials; tool used called a tap
4) Threading; a machining technique in which screw threads are formed around a rod-tool used a die
5) Bending; a machining technique in which a material is curved into a certain shape.