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Metric prefixes

SI units are part of the metric system    . The metric system is convenient for scientific and engineering calculations because the units are categorized by factors of 10. [link] gives metric prefixes and symbols used to denote various factors of 10.

Metric systems have the advantage that conversions of units involve only powers of 10. There are 100 centimeters in a meter, 1000 meters in a kilometer, and so on. In nonmetric systems, such as the system of U.S. customary units, the relationships are not as simple—there are 12 inches in a foot, 5280 feet in a mile, and so on. Another advantage of the metric system is that the same unit can be used over extremely large ranges of values simply by using an appropriate metric prefix. For example, distances in meters are suitable in construction, while distances in kilometers are appropriate for air travel, and the tiny measure of nanometers are convenient in optical design. With the metric system there is no need to invent new units for particular applications.

The term order of magnitude    refers to the scale of a value expressed in the metric system. Each power of 10 size 12{"10"} in the metric system represents a different order of magnitude. For example, 10 1 , 10 2 , 10 3 size 12{"10" rSup { size 8{1} } ,`"10" rSup { size 8{2} } ,`"10" rSup { size 8{3} } } {} , and so forth are all different orders of magnitude. All quantities that can be expressed as a product of a specific power of 10 size 12{"10"} are said to be of the same order of magnitude. For example, the number 800 size 12{"800"} can be written as 8 × 10 2 , and the number 450 can be written as 4. 5 × 10 2 . Thus, the numbers 800 and 450 are of the same order of magnitude: 10 2 . Order of magnitude can be thought of as a ballpark estimate for the scale of a value. The diameter of an atom is on the order of 10 9  m, while the diameter of the Sun is on the order of 10 9  m.

Metric prefixes for powers of 10 and their symbols
Prefix Symbol Value See Appendix A for a discussion of powers of 10. Example (some are approximate)
exa E 10 18 size 12{"10" rSup { size 8{"18"} } } {} exameter Em 10 18  m size 12{"10" rSup { size 8{"18"} } " m"} {} distance light travels in a century
peta P 10 15 size 12{"10" rSup { size 8{"15"} } } {} petasecond Ps 10 15  s size 12{"10" rSup { size 8{"15"} } " s"} {} 30 million years
tera T 10 12 size 12{"10" rSup { size 8{"12"} } } {} terawatt TW 10 12  W size 12{"10" rSup { size 8{"12"} } `W} {} powerful laser output
giga G 10 9 size 12{"10" rSup { size 8{9} } } {} gigahertz GHz 10 9  Hz size 12{"10" rSup { size 8{9} } `"Hz"} {} a microwave frequency
mega M 10 6 size 12{"10" rSup { size 8{6} } } {} megacurie MCi 10 6  Ci size 12{"10" rSup { size 8{6} } `"Ci"} {} high radioactivity
kilo k 10 3 size 12{"10" rSup { size 8{3} } } {} kilometer km 10 3  m size 12{"10" rSup { size 8{3} } " m"} {} about 6/10 mile
hecto h 10 2 size 12{"10" rSup { size 8{2} } } {} hectoliter hL 10 2  L size 12{"10" rSup { size 8{2} } " L"} {} 26 gallons
deka da 10 1 size 12{"10" rSup { size 8{1} } } {} dekagram dag 10 1  g size 12{"10" rSup { size 8{1} } `g} {} teaspoon of butter
10 0 size 12{"10" rSup { size 8{0} } } {} (=1)
deci d 10 1 size 12{"10" rSup { size 8{ - 1} } } {} deciliter dL 10 1  L size 12{"10" rSup { size 8{ - 1} } `L} {} less than half a soda
centi c 10 2 size 12{"10" rSup { size 8{ - 2} } } {} centimeter cm 10 2  m size 12{"10" rSup { size 8{ - 2} } `m} {} fingertip thickness
milli m 10 3 size 12{"10" rSup { size 8{ - 3} } } {} millimeter mm 10 3  m size 12{"10" rSup { size 8{ - 3} } `m} {} flea at its shoulders
micro µ 10 6 size 12{"10" rSup { size 8{ - 6} } } {} micrometer µm 10 6  m size 12{"10" rSup { size 8{ - 6} } `m} {} detail in microscope
nano n 10 9 size 12{"10" rSup { size 8{ - 9} } } {} nanogram ng 10 9  g size 12{"10" rSup { size 8{ - 9} } `g} {} small speck of dust
pico p 10 12 size 12{"10" rSup { size 8{ - "12"} } } {} picofarad pF 10 12  F size 12{"10" rSup { size 8{ - "12"} } F} {} small capacitor in radio
femto f 10 15 size 12{"10" rSup { size 8{ - "15"} } } {} femtometer fm 10 15  m size 12{"10" rSup { size 8{ - "15"} } `m} {} size of a proton
atto a 10 18 size 12{"10" rSup { size 8{ - "18"} } } {} attosecond as 10 18  s size 12{"10" rSup { size 8{ - "18"} } `s} {} time light crosses an atom

Unit conversion and dimensional analysis

It is often necessary to convert from one type of unit to another. For example, if you are reading a European cookbook, some quantities may be expressed in units of liters and you need to convert them to cups. Or, perhaps you are reading walking directions from one location to another and you are interested in how many miles you will be walking. In this case, you will need to convert units of feet to miles.

Questions & Answers

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Uday Reply
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Uday
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Aeesha
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Pixel
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KEMZO
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Uday
what's a demand
Edward Reply
it is the quantity of commodities that consumers are willing and able to purchase at particular prices and at a given time
Munanag
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Omed
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Bashir
Demand is a various quantity of a commodities that a consumer is willing and able to buy at a particular price within a given period of time. All other things been equal.
Vedzi
State the law of demand
Vedzi
The desire to get something is called demand.
Mahabuba
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Random Reply
Why in monopoly does the firm maximize profits when its marginal revenue equals marginal cost
astrid Reply
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Falma Reply
If it is known that the base change of RM45 million, the statutory proposal ratio of 7 per cent, and the public cash holding ratio of 5 per cent, what is the proposed ratio of bank surplus to generate a total deposit of RM 300 million? 
Jeslyne Reply
In a single bank system, a bank can create a deposit when it receives a new deposit in cash. If a depositor puts a cash deposit of RM10,000 into the bank, assume the statutory reserve requirement is 7% and the bank adopts a surplus reserve of 8%. a. Calculate the amount of deposits made at the end o
Jeslyne
the part of marginal revenue product curve lies in the _ stage of production is called form demand curve for variable input.
Bashir Reply
The cost associated with the inputs owned by the farmer is termed as
Bashir
the cost associated with inputs owned by the farmer is termed as ____
Bashir
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Nwobodo Reply
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Eben
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myo
we study economics the know how to use our resources and where to put it
Mamoud
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Nwobodo
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Gloria
we study economics only to know how to effectively and efficiently allocate our limited resource in other to meet our unlimited wants
Kpegba
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Yajanyi Reply
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ibrahim
Adam smith
Somnath
professor Lionel Robins
Abraham
adam smith
albert
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Barsharani
marshall
Aadi
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Laila
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Mamoud
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Bongani
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Omed
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Kitojo Reply
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BENJAMIN Reply
This is the price In which quantity demanded is equal to the quantity supplied.
Binta
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Udoh
is when the price of two item is equal
Mamoud
is the market price at which the demand curve and supply curve of particular commodity interest.
Kpegba
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equilibrium price is when prices are equal
Ramon
equilibrium price is a point at which demand and supply curve meet
Vedzi
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Gloria Reply
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ibrahim
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Kitojo
because it is subjected to human decisions
Kpegba
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Multin
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Mary Reply
We think, that the legal tender is a form of payment of a debt or anything related, but which is not necessarily money. that can be bank notes, or coins for instance. but the bottom line is the legal tender is required to be recognized by the law, but it varies according to the jurisdiction.
Pierre
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Mary
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Mary
legal tender is anything that can be accepted for payment within a country
Tyson
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Philo
is Something legally accepted in a particular place
Mamoud
Who is a liquidator?
Isah Reply
pls,who is a legal tender
Mary
We think, that the legal tender is a form of payment of a debt or anything related, but which is not necessarily money. that can be bank notes, or coins for instance. but the bottom line is the legal tender is required to be recognized by the law, but it varies according to the jurisdiction.
Pierre
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Source:  OpenStax, Kinematics. OpenStax CNX. Sep 11, 2015 Download for free at https://legacy.cnx.org/content/col11878/1.5
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