Deck 17: Engineering Materials

Question 1

The lower the viscosity value is, the more resistance the fluid offers to flow.

Answer 1

False

Question 2

The modulus of rigidity is a measure of how easily a material will stretch when pulled or how well the material will shorten when pushed.

Answer 2

False

Question 3

When copper is alloyed with zinc it is commonly called

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

Answer 3

A

Question 4

Which of the following materials are considered lightweight metals?

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

Question 5

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

Question 6

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 7

A fluid's ______________ represents how compressible the fluid is.How easily can one reduce the volume of the fluid when the fluid pressure is increased?

A)modulus of rigidity
B)density
C)viscosity
D)bulk modulus

Question 8

Alcohol has a lower vapor pressure value than water.

Question 9

Concrete is stronger in tension than it is in compression.

Question 10

Aluminumand its alloys have densities that are approximately one-third the density of steel.

Question 11

The value of heat capacity represents the amount of thermal energy required to raise the temperature of 1 kilogram mass of a material by 1°C.Materials with large heat capacity values are good at storing thermal energy.

Question 12

Material properties depend on many factors, including how the material was processed, its age, its exact chemical composition, and any nonhomogeneity or defect within the material.

Question 13

Titaniumhas an excellent strength-to-weight-ratio.Titanium is used in applications where relatively high temperatures, exceeding 400°C up to 600°C, are expected.

Question 14

Most of the mass of the earth comes from the mantle.The mantle is made up of molten rock that lies underneath the crust and makes up nearly 84% of the Earth's volume.

Question 15

Fluids with low vapor pressure values will not evaporate as quickly as those with high values of vapor pressure.

Question 16

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 17

The coefficient of linear expansion can be used to determine the change in the length (per original length) of a material that would occur if the temperature of the material were changed.

Question 18

As design engineers, whether you are designing a machine part, a toy, a frame for a car, or a structure, the selection of material is an important design decision.

Question 19

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

Question 20

Modulus of elasticity is a measure of how easily a material can be twisted or sheared.

Question 21

What is normally called concrete consists of three main ingredients: aggregate, cement, and water.

Question 22

Plastics are often classified into two categories:

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

Question 23

Bronze is an alloy of copper and tin.

Question 24

Polymers are the backbone of what we call plastics.

Question 25

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

Question 26

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 27

Concrete is stronger in tension than it is in compression.

Question 28

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

Question 29

The 18/8 stainless steel table ware and kitchen ware 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 30

Timber is commonly classified as

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

Question 31

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

Question 32

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

Question 33

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

A)Ordinary glass
B)Silica glass
C)None of the above

Question 34

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

Question 35

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

Question 36

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

Question 37

Steel is an alloy of iron with approximately

A)2% or less carbon
B)20% or less carbon
C)35% or less carbon
D)50% or less carbon

Question 38

Cast iron is considered a ductile material.

Question 39

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

Question 40

Wood is an anisotropic material, meaning that its properties are direction-dependent.

Question 41

The term fluids refers to liquids, not gases.

Question 42

Examples of fibers used in the construction of composite materials include

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

Question 43

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

A)78% oxygen, 21% nitrogen, and less than 1% carbon dioxide.
B)78% nitrogen, 21% oxygen, and less than 1% argon.
C)78% oxygen, 21% carbon dioxide, and less than 1% helium.
D)78% oxygen, 21% water vapor, and less than 1% ozone.

Question 44

Air is a mixture of mostly oxygen, and small amounts of other gases.

Question 45

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 46

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

Question 47

The air surrounding the earth can be divided into four distinct regions:

Question 48

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

Question 49

Metallic oxides are added to give glass various colors.

Question 50

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

Question 51

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 52

Composites may be classified into

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

Question 53

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 54

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

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

Question 55

The layer of air closest to the earth's surface is called the troposphere and plays an important role in shaping our weather.

Question 56

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

Question 57

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 58

Most people feel comfortable when the relative humidity is around

A)10% to 30%
B)30% to 50%
C)50% to 70%
D)70% to 90%

Question 59

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

A)Ordinary glass
B)Silica glass

Question 60

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

Question 61

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

Question 62

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

Question 63

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

A)
B)
C)
D)

Question 64

Water is a common engineering material.

Question 65

Groundwater refers to water that has collected on the ground.

Question 66

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