Deck 17: Engineering Materials

Question 1

Concrete is commonly reinforced with steel bars or steel mesh to

A) increase its rigidity.
B) increase its weight.
C) increase its load-bearing capacity.
D) none of the above

Answer 1

C

Question 2

The strength-to-weight ratio is defined as

A) the ratio of the strength of the material to its weight.
B) the ratio of the strength of the material to its specific weight.
C) the ratio of the strength of the material to its mass.
D) the ratio of the strength of the material to its modulus of elasticity.

Answer 2

B

Question 3

Modulus of elasticity is a measure of how easily a material will stretch when pulled or
how well the material will shorten when pushed.

Answer 3

True

Question 4

Precast concrete slabs, blocks, and structural members are fabricated in less time with
less cost in factory settings where surrounding conditions are controlled.

Question 5

Timber is commonly classified as

A) softwood.
B) hardwood.
C) medium density fiber.
D) softwood and hardwood.

Question 6

Cast iron is considered a ductile material.

Question 7

Concrete is stronger in tension than it is in compression.

Question 8

The value of electrical resistivity is a measure of the resistance of material to the flow
of electricity.

Question 9

Steel is approximately

A) two times stiffer than aluminum alloys.
B) four times stiffer than aluminum alloys.
C) three times stiffer than aluminum alloys.
D) ten times stiffer than aluminum alloys.

Question 10

In general, under axial loading (when pulled), wood is stronger in a direction parallel
to the grain than it is in a direction across the grain.

Question 11

Concrete is stronger in tension than it is in compression.

Question 12

High alloy steels contain more than 8% $8 \%$ of alloying elements.

Question 13

Steel is an alloy of iron with approximately

Question 14

When copper is alloyed with zinc it is commonly called

A) brass.
B) bronze.
C) aluminum bronze.
D) zinc-copper.

Question 15

In general, the higher the density of wood, the lower the strength.

Question 16

Wood is stronger in a direction normal to the grain when it is bent.

Question 17

Alcohol has a lower vapor pressure value than water.

Question 18

In general the properties of materials may be divided into three groups.

A) electrical, mechanical, thermal
B) viscosity, density, temperature
C) resilience, toughness, heat capacity
D) none of the above

Question 19

The $18 / 8$ 8 stainless steel tableware and kitchenware products contain

A) $18 \%$ chromium and $8 \%$ copper.
B) $18 \%$ copper and $8 \%$ chromium.
C) $18 \%$ chromium and $8 \%$ aluminum.
D) $18 \%$ chromium and $8 \%$ nickel.

Question 20

Which of the following materials are considered lightweight metals?

A) Aluminum
B) Titanium
C) Magnesium
D) All of the above

Question 21

Composite materials consist of two main ingredients: matrix material and fibers.

Question 22

Air is often used

A) as a cooling and heating medium.
B) in controlling thermal comfort in buildings.
C) as a controlling medium to turn equipment on and off.
D) to drive power tools.
E) all of the above

Question 23

Polymers are the backbone of what we call plastics.

Question 24

Which type of glass has the higher coefficient of thermal expansion?

A) Ordinary glass
B) Silica glass

Question 25

Silicon is a nonmetallic chemical element that is used in the manufacture of
transistors and electronic computer chips.

Question 26

Metallic oxides are added to give glass various colors.

Question 27

Fiber optics is the branch of science that deals with transmitting data, voice, and
images through thin plastic or glass fibers.

Question 28

Most of the ultraviolet radiation arriving on earth from the sun is absorbed by

A) air.
B) nitrogen.
C) water vapor.
D) ozone.

Question 29

Silicone is a synthetic compound that is commonly used in lubricants, varnishes, and
waterproofing products.

Question 30

The ratio of the mass of water vapor to the mass of dry air is known as

A) dew point.
B) absolute humidity.
C) relative humidity.
D) none of the above

Question 31

The most widely used form of glass is soda-lime-silica glass.

Question 32

Which type of glass is better in high-temperature applications?

A) Ordinary glass
B) Silica glass

Question 33

Air and water are among the most abundant fluids on earth.

Question 34

Composites may be classified into

A) polymer-matrix composites.
B) metal-matrix composites.
C) ceramic-matrix composites.
D) all of above

Question 35

There are two common ways of expressing the amount of water vapor in air:

A) dew point and relative humidity.
B) dew point and absolute humidity.
C) absolute humidity and relative humidity.
D) none of the above

Question 36

Composites are created by combining two or more solid materials to make a new
material that has properties that are superior to those of the individual components.

Question 37

Plastics are often classified into two categories:

A) foams and vinyls
B) thermoplastics and thermosets
C) flexible and rigid
D) transparent and opaque

Question 38

The term fluids refers to liquids, not gases.

Question 39

Examples of fibers used in the construction of composite materials include

A) glass.
B) graphite.
C) silicon carbide fibers.
D) all of above

Question 40

The earth's atmosphere, which we refer to as air, is a mixture of approximately

Question 41

Mechanical engineers need to understand the thermophysical properties of liquid
water and steam when designing power plants.

Question 42

Approximately what fraction of the earth's surface is covered with water?

Question 43

Water is a common engineering material.

Question 44

The higher the air temperature, the less water vapor the air can hold before it is fully
saturated.

Question 45

Water is used as a cutting tool to cut stone and steel.

Question 46

Surface water refers to water in reservoirs, lakes, rivers, and streams.

Question 47

Groundwater refers to water that has collected on the ground.

Question 48

The ratio of the amount of moisture in the air to the maximum amount of moisture that air can hold is known as

A) dew point.
B) absolute humidity.
C) relative humidity.
D) none of the above

Question 49

Most people feel comfortable when the relative humidity is around

Question 50

Understanding the properties of liquid water and steam is important to which engineering discipline?

A) Mechanical engineering
B) Civil engineering
C) Manufacturing engineering
D) All of the above