Fundamentals of Dimensional Metrology

Connie L. Dotson

Chapter 2 LANGUAGE AND SYSTEMS OF MEASUREMENT - all with Video Answers

Educators

Chapter Questions

Problem 1

Ambiguity is the enemy of dimensional metrology. Which of the following best describes a figure with four sides, each of which is $21 / 2$ in. in length?
a. Polyhedron
b. Patallelepiped
c. Square
d. Parallelogram

Teresa Fuston

Numerade Educator

01:38

Problem 2

The principal dimensional measurement is length. Which of the following is the best definition of length?
a. A dimension
b. The shortest distance between two points
c. The number of units of measurement that separates two points
d. The opposite of width

Jennifer Hudspeth

Numerade Educator

Problem 3

Which of the following terms is not essential in defining a length measurement?
a. Reference point
b. Unit of measurement
c. Tolerance
d. Measured point

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Problem 4

In which one or more of the following characteristics does a dimension differ from a length?
a. A dimension is an intended size, whereas a length is the measured size.
b. A length may be a decimal, but a dimension is a whole number.
c. A dimension must be determined by measurement, whereas a length is stated on the drawing of the part.
d. Lengths have tolerances, whereas dimensions do not.

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Problem 5

The primary purpose of dimensional measurement is to:
a. show how precise a part is
b. show how close the manufacturer can produce parts
c. justify the price
d. communicate the designer's intent

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Problem 6

Identify each of the following situations in which dimensional measurement sometimes is not needed.
a. Manufacturing farm machinery
b. Hand fitting one part to work in conjunction with another
c. When tolerances are greater than $\pm 0.005$ in.
d. When fluctuating temperature causes parts to expand and contract continuously

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Problem 7

When measurements are repeatedly taken on the same unit, the extent to which an instrument replicates its measurements is:
a. accuracy
b. range
c. precision
d. discrimination

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01:15

Problem 8

Which of the following best describes the reference point?
a Point at which any measurement begins
b. Position identified on a drawing as the end of a measurement
c. Furthest point from the measured point
d. Highest point above the reference plane

Rashmi Sinha

Numerade Educator

03:09

Problem 9

Which of the following is the end of a measurement?
a. Congruent point
b. Instrument reading
c. Measurement stop
d. Measured point

Anurag Kumar

Numerade Educator

Problem 10

Part features designate the portion of a part that may be considered separately from the part itself.
a. True
b. False

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01:05

Problem 11

How many . 001 inches are there in one inch?
a. 1
b. 100
c. 1,000
d. 10,000

Brandon Fox

Numerade Educator

00:16

Problem 12

Which of the following best defines an edge?
a. The sharp corners of the part
b. The intersection of a plane with another plane
c. The cutting portion of an instrument
d. Conical section

Cory Kuzinski

Numerade Educator

Problem 13

Which of the following best describes male features?
a. Total lengths, heights, and widths
b. Round rods or tubular parts
c. Features bounded by outside dimensions
d. Features larger than female features

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01:40

Problem 14

If $1 \mathrm{~mm}=.0394$ inches, 700 millimeters equal how many inches?
a. 35.53
b. 275.8
c. 27.58
d. 003

Crystal Wang

Numerade Educator

Problem 15

The ability of two or more inspectors to obtain consistent results repeatedly when measuring the same set of parts and the same measuring instruments is called:
a. accuracy
b. precision
c reproducibility
d. error

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01:38

Problem 16

One shooter fires 10 shots in a group 5 in. in diameter but all are off the target. Then a second shooter has a group $10 \mathrm{in}$. in diameter but three shots are through the $\mathrm{X}$-ring. Which of the following statements are the most likely to be correct?
a. The first shooter is precise but not as accurate as the second shooter.
b. The second shooter is the luckiest.
c. The second shooter is both precise and accurate.
d. The first shooter is precise but inaccurate, whereas the second shooter is more precise and more accurate.

David Collins

Numerade Educator

Problem 17

Accuracy may be defined several ways. Which of the following is correct?
a. Accuracy is the measure of precision.
b. Accuracy is the measure of conformity.
c. Accuracy is the measure of reliability.
d. Accuracy is the best synonym for precision.

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Problem 18

Which of the following terms relates most closely to precision?
a. Close tolerance
b. High machining cost
c. Low quality compared with accuracy
d. Refinement of measurement readings

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Problem 19

Which of the following does reliability depend on?
a. High-grade measuring instruments
b. Both accuracy and precision
c. Lots of luck
d. Limited production

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02:33

Problem 20

Can either accuracy or precision be improved without respect for the other value? Select the correct statement:
a. Neither can be changed without affecting the other.
b. Fither can be increased without affecting the other.
c. Precision can be increased without an increase in accuracy.
d. Accuracy can have only limited increase without requiring an increase in precision.

Mahendra Kumar

Numerade Educator

Problem 21

Tolerances are specified for machined parts for which of the following reasons?
a. Manufacturing equipment has inherent variation
b. To ensure proper fit between mating parts
c. The designer wasn't sure of the exact measurement to specify
d. Both $a$ and $b$

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01:32

Problem 22

The earliest recorded length standard was:
a. The ulna
b. The length of the monarch's foot
c. The cubit
d. The Egyptian pyramids

Teresa Fuston

Numerade Educator

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Problem 23

What was the primary purpose of the earliest recorded standard?
a. To ensure fair payment of taxes
b. To practice early medicine
c. To ensure that parts mated in building construction
d. To mix cement in buifding the pyramids

James Kiss

Numerade Educator

Problem 24

What is the chief similarity between the use of this first recorded standard and present-day practices?
a. High cost of reliable measurement
b. Use of metal standards
c. Need for inches and fractions of inches
d. Requirement that working standards agree with the master standard

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02:55

Problem 25

The English system and the metric system differ in the origin of their standards. Which of the following best describes those origins?
a. Metric standards derived from the standards in use by the crafts guilds, whereas the English standards were those used by the peasants and small merchants.
b. Both were by decree of the existing governments.
c. The metric standardswere derived from the diameter of the earth, whereas the English standards were selected by the House of Parliament.
d. The metric standards were placed in force by the Revolutionary Committee, whereas the English standards were already in use.

Ethan Fuhrman

Numerade Educator

01:08

Problem 26

Why have light waves replaced metal bars for the master standards of length?
a. The platinum-iridium bars are very expensive, but light is free.
b. They are easier to use in the dark.
c. Light wave standards are more readily reproducible to greater accuracy than metal bars.
d. The use of light waves avoids political considerations.

Coleen Amado

Numerade Educator

Problem 27

There are many ways that measurement systems can be compared. Which of the following are the three best ways?
a. Metrological superiority, computational advantage, and communications ability
b. Finest discrimination, greatest accuracy, and easiest convertibility
c. Agreement among nations, historical precedent, and general acceptability
d. Lowest cost added to the manufacture of products, most easily available gages and measuring instruments, and easy-to-understand quality control procedures

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01:20

Problem 28

Round off 25.7853901 to two significant digits.
a. 25.786
b. 25.78
c 25.79
d 26

Nicole Smina

Numerade Educator

Problem 29

Each of the following lists is fully correct. However, one of them comes closest for defining the four most essential qualities of a measurement system. Which is it?
a. Greatest measuring ability, least errors, least time to conduct measurements, least destruction to workpieces while being measured
b. Lowest cost; widest range of direct measurement; adaptability to angles, surface finishes, and radif as well as lengths; minimum errors
c. Easiest computations, self-canceling errors, clearly visible minimum scale divisions, same meaning in all languages
d. Optimum measuring ability, minimum errors, minimum time required to measure, minimum cost

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01:04

Problem 30

Le Système International d'Unités is abbreviated:
a. LSIU
b. SI
c. IU
d. $\mathrm{mm}$

Tyler Moulton

Numerade Educator

Problem 31

Which of the following are good reasons to use the decimal-inch system?
a. Convertibility in and out of the metric system is easy.
b. Rounding off is easier than it is with the English system using fractions.
c. The finest division is close to the minimum resolving power of the human eye.
d. It does not need to be calibrated to the international meter.

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02:18

Problem 32

Which of the following correctly represents a gentimeter and a kilometer?
) $10^{-2}, 101^3$
b. $10^1, 10^{-1}$
c. $10^2, 10^2$
d. $10^{-2}, 10^4$

Patsy Naomi

Numerade Educator

Problem 33

Which of the following best explains the reasons for rounding off?
a. Elimination of numbers over 5
b. Averaging the computational error
c. Elimination of meaningless digits
d. Simplifying computations

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01:53

Problem 34

What is the exception to the rule for rounding off?
a. Values over 9 should be left undisturbed.
b. Calculations involving values of different decimal places should not be rounded off.
c. The final rounding should be obtained from the most precise value.
d. Values beyond four decimal places should not be rounded off.

Qiao Ruan

Numerade Educator