Mathematics
Metric and Imperial Units
Metric and Imperial units are systems of measurement used to quantify length, weight, volume, and other quantities. The metric system is based on units such as meters, grams, and liters, while the Imperial system uses units like feet, pounds, and gallons. In mathematics, understanding and converting between these two systems is important for solving problems involving measurement.
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12 Key excerpts on "Metric and Imperial Units"
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Learning Press(Publisher)
Metric units are universally used in scientific work, and widely used around the world for personal and commercial purposes. A standard set of prefixes in powers of ten may be used to derive larger and smaller units from the base units. The International System of Units is the official system of measurement for all nations in the world except for Burma, Liberia, and the United States. (Some sources identify Burma or Liberia as metric, however.) However, a number of other jurisdictions have laws mandating or permitting other systems of measurement in some or all contexts, such as the United Kingdom – where for example the Traffic Sign Regulations (TSRGD) only allow distance signs displaying imperial units (miles or yards) – or Hong Kong. In the United States, metric units are widely used in science, military, and industry, but customary units predominate in household use. At retail stores, the litre is a commonly used unit for volume, especially on bottles of beverages, and milligrams are used to denominate the amounts of medications, rather than grains. Also, other standardised measuring systems other than metric are still in universal international use, such as nautical miles and knots in international aviation. Overview Countries which have officially adopted the metric system (green) . Three nations out of 203 have not officially adopted the International System of Units as their primary or sole system of measurement: Burma, Liberia, and the United States. ___________________________ WORLD TECHNOLOGIES ___________________________ One goal of the metric system is to have a single unit for every physical quantity; another important one is not needing conversion factors when making calculations with physical quantities. All lengths and distances, for example, are measured in metres, or thousandths of a metre (millimetres), or thousands of metres (kilometre), and so on.
eBook - PDFEngineering Technology NQF2 SB
TVET FIRST
- Jowaheer Consulting and Technologies Business Programme Developments(Author)
- 2013(Publication Date)
- Macmillan(Publisher)
Different measurement systems Until 1968, South Africa used the imperial system of measurement. South Africa gradually introduced the metric system of measurement using SI units over a number of years. Finally, in 1973, the use of imperial measurements was prohibited. The imperial system of measurement was the system used throughout the British Empire. Its base units were length expressed in feet, mass expressed in pounds and time expressed in seconds. A big disadvantage of this system, as you will see later, is that it is not based on the decimal system. The United States of America (USA) uses the United States customary system or American system. Although this system is similar in many respects to the British imperial system, there are a number of important numerical differences. The International System of Units (SI) The International System of Units is abbreviated SI from its French name, le Système International d’unités . Almost all countries in the world use this system in science and commerce. The main exceptions are the USA, Liberia and Myanmar (Burma). The SI is a system of units of measurement. There are seven base units and numerous derived units. It is also a metric, or decimalised, system based on the number ten. The base units and their physical quantities are: • metre for length • kilogram for mass • second for time • ampere for electric current • kelvin for temperature • candela for luminous intensity • mole for the amount of substance. All the other SI units are derived from these seven base units. In a decimalised system, all units are related by powers of 10 and are identified by prefixes. This makes the conversion of units easier. For example, it is easy to convert metres to millimetres by simply moving the decimal point – 1,456 metres is 1 456 millimetres.
eBook - PDFElectrical Principles & Practice NQF2 SB
TVET FIRST
- Jowaheer Consulting and Technologies(Author)
- 2013(Publication Date)
- Macmillan(Publisher)
Different measurement systems Until 1968, South Africa used the imperial system of measurement. South Africa gradually introduced the metric system of measurement using SI units over a number of years. Finally, in 1973, the use of imperial measurements was prohibited. The imperial system of measurement was the system used throughout the British Empire. Its base units were length expressed in feet, mass expressed in pounds and time expressed in seconds. A big disadvantage of this system, as you will see later, is that it is not based on the decimal system. The United States of America (USA) uses the United States customary system or American system. Although this system is similar in many respects to the British imperial system, there are a number of important numerical differences. The International System of Units (SI) The International System of Units is abbreviated SI from its French name, Système International d’Unités . Almost all countries in the world use this system in science and commerce. The main exceptions are the USA, Liberia and Myanmar (Burma). The SI is a system of units of measurement. There are seven base units and numerous derived units. It is also a metric, or decimalised, system based on the number ten. The base units and their physical quantities are: • metre for length • kilogram for mass • second for time • ampere for electric current • kelvin for temperature • candela for luminous intensity • mole for the amount of a substance. Lord Kelvin, a scientist, said: When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of science. 4 Topic 1 SI units of measurement All the other SI units are derived from these seven base units.
eBook - PDFMaterials, Structures, and Standards
All the Details Architects Need to Know But Can Never Find
- Julia McMorrough(Author)
- 2006(Publication Date)
- Rockport Publishers(Publisher)
customary units system, referred to in the United States as English units or standard units. The latter is an irregular system based on imperial units once used in the United Kingdom and the British Commonwealth. The metric system has become the universally accepted system of units in science, trade, and commerce. In the United States, however, where the Metric Conversion Act of 1975 established SI as the preferred system of weights and measures for trade and commerce, federal laws have yet to mandate SI as the official system, making its use still primarily voluntary. Several U.S. agencies, including the American National Metric Council (ANMC) and the United States Metric Association (USMA), are working to estab-lish SI as the official measurement system, a process known as metrication. Though the architectural, engineering, and building trades have been slow to make a full transi-tion, nearly all federally funded building projects are now required to be in SI units. UNITS OF MEASURE: CUSTOMARY UNIT DATA Customary units may be shown in a number of ways, including as fractions ( 1 1 / 2 ” ) or as decimals ( 1.5” or 0.125’ ), depending on the more common usage for a particular situation. It should be noted that, though not the case here, exponents can be used with abbreviations that designate area or volume; for example, 100 ft . 2 for area or 100 ft . 3 for volume. Customary Unit Relation to Other of Measure Customary Units inch (in. or “ ) 1 / 12 ft. foot (ft. or ‘ ) 12 in. 1 / 3 yd. yard (yd.) 36 in. 3 ft. rod (rd.), pole, or perch 16 1 / 2 ft. 5 1 / 2 yd. chain 4 rd. 22 yd. furlong 220 yd. or 40 rd. or 10 chains or 1 / 8 mi. mile (mi.), statute 5,280 ft. or 1,760 yd. or 8 furlongs mile (mi.), nautical 2,025 yd. Customary Unit Relation to Other of Measure Customary Units square inch (sq. in.) 0.007 ( 1 / 142 ) sq. ft. square foot (sq. ft.) 144 sq. in. square yard (sq. yd.) 1,296 sq. in. 9 sq. ft. square pole 30 1 / 4 sq. yd. acre 43,560 sq.
eBook - PDF- Dale Ewen(Author)
- 2018(Publication Date)
- Cengage Learning EMEA(Publisher)
And the inherent simplicity of the metric system of measurement and standardization of weights and measures have led to major cost savings in industries that have converted to it. Most major U.S. industries, such as the automotive, aviation, and farm implement industries, as well as the Department of Defense and other federal agencies, have effectively converted to the metric system. In some industries, you—the student and worker—will need to know and use both systems. The SI metric system has seven base units, as shown in Table 3.1. Other commonly used metric units are shown in Table 3.2. The metric system, a decimal or base 10 system, is very similar to our decimal number system. It is an easy system to use, because calculations are based on the number 10 and its multiples. The SI system has special prefixes that name multiples and submultiples; these can be used with almost all SI units. Table 3.3 shows the prefixes and the corresponding symbols. Because the same prefixes are used with most all SI metric units, it is not necessary to memorize long lists or many tables. Table 3.1 | Seven Base Metric Units Basic unit SI abbreviation For measuring metre* kilogram second ampere kelvin candela mole m kg s A K cd mol length mass time electric current temperature light intensity molecular substance *At present, there is some difference of opinion on the spelling of metre and litre. We have chosen the “re” spelling because it is the internationally accepted spelling and because it distinguishes the unit from other meters, such as parking meters and electricity meters. Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience.
- James Deitz, James Southam(Authors)
- 2015(Publication Date)
- Cengage Learning EMEA(Publisher)
However, once again, it never happened. Today the United States is the only industrialized country in the world which has not adopted the metric system. Although not officially adopted by the United States today, the metric system is used in many areas of personal and business activities. Companies that export their products outside the United States use the metric system for their export items. Internationally oriented corporations like GM, IBM, and Microsoft have adopted the metric system for use in many of their manufacturing processes for global products. Many high schools and universities have running tracks and engage in competitive events measured in meters. United States athletes who compete in the Olympic Games and other international contests compete in meters. Many foreign-made automobiles sold in the United States have speedometers that indicate speed in both miles and kilometers. Virtually all pharmaceutical products manufactured in the United States and imported by pharmaceutical companies are dispensed with their quantities indicated in “grams.” Our commonly used music CDs and video DVDs comply with an international metric standard established as 12 centimeters in diameter. Because our economy is now global and world travel is so popular, it is important that a person is able to understand and use the metric system. To participate in the world economy, one needs to use, calculate, and convert measurements between the US Tradi-tional and the International System of Units (SI). DECIMAL SYSTEM The metric system is a decimal system. Prefixes and/or symbols are added to the metric base unit to indicate powers of 10, that is, 10, 100, 1,000. Likewise, prefixes or symbols are added to the base unit to indicate 1/10, 1/100, or 1/1, 000 part of the unit. Basic Elements of the International System of Units (SI) Copyright 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part.
eBook - ePub- Beat Jeckelmann, Robert Edelmaier, Beat Jeckelmann, Robert Edelmaier(Authors)
- 2023(Publication Date)
- De Gruyter Oldenbourg(Publisher)
International system of units: Concept and current design
Beat JeckelmannMuntelier , SwitzerlandAbstract
Measurement processes determine our everyday life. A system of measurement units that is valid and accepted worldwide and across all disciplines, is the prerequisite for measurement results to be comparable and interpreted correctly everywhere. After great confusion in the Middle Ages, the decisive impulse for the design of such a system came from France. At the time of the French Revolution, the foundations for the decimal metric system were laid by tracing the unit of length, the meter, back to part of the Earth’s meridian. Finally, with the signing of the Metre Convention in 1875, the step was taken toward standardizing the units of measurement beyond national borders. After that, the metric system was able to expand and develop over the years according to the increasing needs of science and technology. It became the International System of Units (SI) with seven base units today. It can be used in all scientific and practical measurement tasks and is rightly regarded as the technical language of science. The SI remains adaptable to the needs of all areas of science and adjustments are made when necessary. In 2018, a fundamental revision of the SI took place. For the first time, the SI became free of artefacts. The realization of units is now conceptually detached from the definition. A unit defined by the fixed value of natural constants can be realized in accordance with the laws of physics. Improvements in realization are possible without having to redefine the unit.In this chapter, a brief outline of the history and background of the SI is given, the 2018 revision of the SI is explained, and the resulting possibilities are outlined.1 Introduction
Measurement determines our everyday life. There is hardly any activity that does not involve a measurement task in some way, be it in the private sphere, in the practice of a craft, in industry or in research. William Thomson, later Lord Kelvin, expressed the importance of measuring at the end of the eighteenth century as follows:
eBook - ePubOlin's Construction
Principles, Materials, and Methods
- H. Leslie Simmons(Author)
- 2011(Publication Date)
- Wiley(Publisher)
Chapter 24 The Metric System of Measurement Introduction The History of Measurement The Metric System The International System of Units SI Units for Design and Construction Conversion of Numerical Values Preferred Dimensions and Coordination Metric Conversions Applicable to This Book Additional Reading Acknowledgments and References IntroductionMetrication is a term coined in Britain to describe metric conversion, which is the process of changing from the customary to the metric system of measurement, including the planning and coordination necessary for the change.The customary system of measurement referred to here is the collection of English and other nonmetric units currently used in the United States. The customary system is also called the inch-pound (I-P) system and this abbreviation is sometimes used in this textbook. The metric system is a system originally developed in France that has been adopted by more than 90% of the nations of the world. It is based on the metre and six other standardized base units . Metric units already in general use include, but are not limited to, the second , ampere , candela, watt , volt , ohm, farad , coulomb , and lumen .Much of the material in this section is based on two current metric standards:1. IEEE/ASTM SI-10, which is a replacement for American Society for Testing and Materials (ASTM) E380-89a, “Standard for Metric Practices.”2.
eBook - PDF- Connie Dotson(Author)
- 2015(Publication Date)
- Cengage Learning EMEA(Publisher)
To determine the best system of measurement, we use three factors: 1. Metrological factor—which act of measurement will yield usable results 2. Computational factor—which system yields fig-ures that we can use mathematically 3. Communicative factor—which system makes it easiest for us to share the measurement with other people In turn, each of these factors must be evaluated by four subcriteria (see Figure 2–17), whether the sys-tems provide: 1. Maximum measurement potential 2. Minimum time required 3. Minimum error potential 4. Minimum cost incurred Metrologically, both the metric and inch sys-tems can handle extremely large measurements and very fine measurements. We use similar instru-ments in both systems; they require about the same time to operate; and they are subject to the same er-rors. However, as a cost consideration, the inch sys-tem requires two sets of scaled instruments: one for fractional measurements and one for decimal-inch measurements. In computational, the metric system’s increments are uniform, whereas the inch system must be con-verted among different terms (inch, foot, yard, rod, and mile) that are not systematically related. Clearly, converting among distances in the same measurement system is easier in metric terminology. In terms of communication, the inch system is easier for most Americans to immediately compre-hend than the metric system. Years of experience with inches, feet, yards, and so forth, give us the mental ref-erences we need to easily understand a measurement. Today, however, manufacturers are competing in a global economy. For example, parts manufac-tured in the Far East must be able to fit precisely with parts made in Europe, and these parts must be able to be replaced by parts made in the United States. Manu-facturers must recognize international demands and adapt manufacturing processes to the accepted stan-dards of the global economy.
eBook - PDF- James Shipman, Jerry Wilson, Charles Higgins, Bo Lou, James Shipman(Authors)
- 2020(Publication Date)
- Cengage Learning EMEA(Publisher)
A smaller cgs system is sometimes used: centimeter, gram, second. 1.5 More on the Metric System Key Questions ● ● What are the four most common metric prefixes? ● ● What is the difference between a cubic centimeter and a milliliter? The SI was established in 1960 to make comprehension and the exchange of ideas among the people of different nations as simple as possible. It now contains seven base units: the meter (m), the kilogram (kg), the second (s), the ampere (A) to measure the flow of electric charge, the kelvin (K) to measure temperature, the mole (mol) to mea- sure the amount of a substance, and the candela (cd) to measure luminous intensity. A definition of each of these units is given in Appendix A. However, we will be concerned with only the first three of these units for several chapters. One major advantage of the metric system is that it is a decimal (base-10) system. The British system is a duodecimal (base-12) system, as 12 inches equals a foot. The base-10 system allows easy expression and conversion to larger and smaller units. A series of metric prefixes is used to express the multiples of 10, but you will only need to be familiar with a few common ones: mega- (M) 1,000,000 (million, 10 6 ) kilo- (k) 1000 (thousand, 10 3 ) centi- (c) 1 100 5 0.01 (hundredth, 10 22 ) milli- (m) 1 1000 5 0.001 (thousandth, 10 23 ) Examples of the relationships of these prefixes follow. 1 megabyte (Mb) is equal to a million bytes. 1 kilogram is equal to 1000 grams (g). 1 meter is equal to 100 centimeters (cm) or 1000 millimeters (mm). 1 millisecond (ms) is equal to 0.001 second (s). (See ● Table 1.2 for more metric prefixes. A more complete list is given in Appendix A Table A.1.) You are familiar with another base-10 system: our currency. A cent is 1 100 of a dollar, or a centidollar. A dime is 1 10 of a dollar, or a decidollar. Tax assessments and school bond levies are sometimes given in mills.
eBook - PDF- John Peterson, Robert Smith(Authors)
- 2019(Publication Date)
- Cengage Learning EMEA(Publisher)
160 SECTION THREE OBJECTIVES After studying this unit you should be able to ● ● Express customary lengths as larger or smaller customary linear units. ● ● Perform arithmetic operations with customary linear units and compound numbers. The United States uses two systems of weights and measures: the American or U.S. customary system and the International System of Units, called the SI metric system. The American customary system is based on the English system of weights and measures and is sometimes called the “English” system. Throughout this book, American customary units are called “customary” units and SI metric units are called “metric” units. Both customary and metric systems include all types of units of measure, such as length, area, volume, and capacity. It is important that you have the ability to measure and compute with both customary and metric units. In the machine trades, linear or length measure is used most often. Throughout this book, linear measure is the primary type of measure presented. However, in Section 6, some fundamentals of area and volume and their applications are presented. Customary (English) Units of Measure UNIT 26 Linear Measurement: Customary (English) and Metric 3 MEASUREMENT DEFINITIONS Measurement is the comparison of a quantity with a standard unit. A linear measurement is a means of expressing the distance between two points; it is the measurement of lengths. A linear measurement has two parts: a unit of length and a multiplier. UNIT 26 CUSTOMARY (ENGLISH) UNITS OF MEASURE 161 3.872 inches 27.18 millimeters Multiplier Unit of Length Multiplier Unit of Length The measurements 3.872 inches and 27.18 millimeters are examples of denominate numbers. A denominate number is a number that specifies a unit of measure. CUSTOMARY UNITS OF LINEAR MEASURE The yard is the standard unit of linear measure in the customary system. From the yard, other units such as the inch and foot are established.
eBook - ePub- (Author)
- 2015(Publication Date)
- For Dummies(Publisher)
If you don’t have little marks between the marked numbers, you need to use some intelligent guesswork. You make the following series of decisions:- Is your reading more or less than halfway between the two marks?
If more than, your answer ends in something bigger than ‘.5’. If less than, your answer ends in something smaller than ‘.5’. If your reading’s just about exactly halfway, your measurement ends in ‘.5’.
- Is your measurement closer to halfway, or closer to one of the marks? Use this question to decide between ‘.6 and .7’ and ‘.8 and .9’ for the last digit if you’re more than halfway, or between ‘.1 and .2’ and ‘.3 or .4’ if you’re less than halfway.
- Make a choice between your two remaining options, largely based on gut feeling and eyesight.
- Tack your decimal digit on to the lower number of the two marks.
Using different units of length
A ruler often has a different scale on each of the two sides: One scale may go from 0 to 30 or 0 to 15 in spaces each measuring a centimetre — about the width of a finger — and the other scale may go from 0 to 12 or from 0 to 6 in inches — about the width of two fingers (all depending on the size of your fingers, obviously).One hundred centimetres make a metre, as the name implies, and centimetres are part of the metric system — the same system that uses kilograms and grams for mass, which I talk about earlier in this chapter. The idea of the metric system is that converting between units is simply a matter of multiplying or dividing by 10, 100 or 1,000.Figure 12.10 shows a conversion chart — one of the most useful tools you can use when converting between different units. Note: Kilometres are the largest units of length and millimetres are the smallest units of length in this chart. Larger and smaller units exist, but this is enough to consider for now.You may notice that this chart is different from the conversion chart used for mass (refer to Figure 12.4
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