Kilo, SI prefix

The CIPM has approved twenty prefixes for SI units (see Table 3) and permits the use of any SI prefix with an SI unit, with one exception. The SI unit for mass, the kilogram, already has a prefix in its name and can have no other SI prefix. To use prefixes with a unit for mass, the rule is to remove the kilo prefix and add the new prefix to gram (unit symbol g), as in milligram and its abbreviation mg. 

These base units can be combined with prefixes in order to derive larger or smaller quantities. For example, we combine the prefix kilo- with the base unit meter to get one kilometer, which has a value of 1000 meters. The SI prefixes are shown on page 44. 

One advantage of any metric system is that it is a decimal system. In SI, a larger or smaller unit for a physical quantity is indicated by an SI prefix, which is a prefix used in the International System to indicate a power of ten. For example, the base unit of length in SI is the meter (somewhat longer than a yard), and 10 meter is called a centi-meter. Thus 2.54 centimeters equals 2.54 X 10 meters. The SI prefixes are fisted in Table 1.3. Only the highlighted ones will be used in this book mega- (10 ), kilo- (10 ), deci- (10 ), centi- (10 ), milli- (10 ), micro- (10 ), nano- (10 ), andpico- (10 ). 

Kilo k peratuiB which had formerly been called degree Kelvin and assigned it the symbol K (without the symbol °). SI prefix for 10. ... 

Note The base unit for mass - kilogram contains the SI prefix kilo , so in this special case multiples of the SI unit are formed by adding the prefix to the unit gram. For example, notation is milligram (mg), and not microkilogram (/ kg). 

Standard meter bar an unchanging, reproducible quantity 1 meter is the distance traveled by light in a vacuum in 1/299,792,458 of a second. Length is one of the seven fundamental quantities in the SI system (see Table 1.1). All other physical quantities have units that can be derived from these seven. SI is a decimal system. Quantities differing from the base unit by powers of ten are noted by the use of prefixes. For example, the prefix kilo means "one thousand" (10 ) times the base unit it is abbreviated as k. Thus 1 kilometer = 1000 meters, or 1 km = 1000 m. The SI prefixes are listed in Table 1.2. 

SI base units include the meter (m), kilogram (kg), second (s), ampere (A), kelvin (K), and mole (mol). Derived quantities such as force (newton, N), pressure (pascal. Pa), and energy (joule, J) can be expressed in terms of base units. In calculations, units should be carried along with the numbers. Prefixes such as kilo- and milli- are used to denote multiples of units. Common expressions of concentration are molarity (moles of solute per liter of solution), molality (moles of solute per kilogram of solvent), formal concentration... 

The metric system and its newer counterpart, SI, use subunits and multiples of units that are equal to powers of 10, and they also use the same prefixes to mean certain fractions or multiples, no matter what primary unit is being modified. The meter is the primary unit of length the gram is the primary unit of mass and the liter (the cubic meter in SI) is the primary unit of volume. The prefixes centi-(0.01), (0.001), and kilo (1000) are used with any of... 

Recall from Chapter 2 that the universal unit system used hy scientists is called Le Systeme Internationale d Unit6s or SI. It is a metric system based on seven base units—meter, second, kilogram, kelvin, mole, ampere, and candela—from which all other units are derived. The size of a unit in a metric system is indicated by a prefix related to the difference between that unit and the base unit. For example, the base unit for length in the metric system is the meter. One tenth of a meter is a decimeter where the prefix deci- means one tenth. And, one thousand meters is a kilometer. The prefix kilo- means one thousand. 

The defining event of a radioactive nuclide is the transformation of its nucleus into the nucleus of another species, that is, radioactive decay. The number of nuclear transformations occurring per unit of time is called activity . Sometimes radioactivity is used instead of activity . The traditional unit of activity has been the Curie (Ci), which is equal to 3.7 X 10 ° nuclear transformations per second. The conversion of radiation units to the international system (Sysfme International d Unit or SI) has now taken place in the United States. The more fundamental unit of activity, the Becquerel (Bq), equal to 1 nuclear transformation per second, has replaced the Curie. Both units of activity are modified by prefixes such as kilo-, milli-, and micro- to achieve standard multiples of the fundamental unit. A listing of the most commonly used prefixes is given in Table 1. 

The prefixes used in the SI and metric systems may be thought of as multipliers. For example, the prefix kilo-indicates multiplication by 1000 or 10, and milli- indicates multiplication by 0.001 or 10. ... 

The SI emit for measuring pressure is the pascal (Pa), named after the French physicist Blaise Pascal (1623-1662). Because the pascal is a small pressure emit, it is more convenient to use the Idlopascal. As you recall from Chapter 1, the prefix kilo- means 1000 so, 1 Idlopascal (kPa) is equivalent to 1000 pascals. One standard atmosphere is equivalent to 101.3 Idlopascals. 

To better describe the range of possible measurements, scientists add prefixes to the base units. This task is made easier because the metric system is a decimal system—a system based on units of 10. The prefixes in Table 2.2 are based on factors of ten and can be used with all SI units. For example, the prefix kilo- means one thousand therefore, 1 km equals 1000 m. Similarly, the prefix milli- means one-thousandth therfore, 1 mm equals 0.001 m. Many mechanical pencils use lead that is 0.5 mm in diameter. How much of a meter is 0.5 mm ... 

The SI unit of mass is the kilogram (kg), which is interesting for a few reasons. It is the only basic SI unit defined with a prefix (kilo) already in place, and it is the only one defined by reference to a physical object—a mass of platinum-iridium held at Sevres in France. To express the large quantities of material that we encounter in the extraction and processing of ores it is usual to use the metric ton (sometimes written toime symbol t) ... 

The SI base unit of length is the meter, a distance slightly longer than a yard. Mass is a measure of the amount of material in an object. The SI base unit of mass is the kilogram (kg), which is equal to about 2.2 pounds (lb). This base unit is unusual because it uses a prefix, kilo-, instead of the word gram alone. We obtain other units for mass by adding prefixes to the word gram. 

Decimal fractions and multiples of metric and SI units are designated by using the prefixes listed in Table G.2. The prefix kilo, for example, means a unit is multiplied by 10 ... 

The SI system is a decimal system. There are base units for mass, length, volume, and so on, and there are prefixes that modify the base units. For example, kilo- means 1,000 a kilogram is 1,000 grams, and a kilometer is 1,000 meters. 

The SI system employs prefix multipUeis (Table 2.2) with the standard imits. These multipliers Aange the value of the imit by powers of 10. For example, the kilometer (km) has the prefix kilo-, meaning 1000 or 10. Therefore ... 

Units Measured quantities usually have units associated with them. The SI unit for length is the meter for mass, the kilogram and for time, the second. Prefix multipliers such as kilo- or milli- are often used in combination with these basic units. The SI units of volume are units of length raised to the third power liters or milliliters are often used as well. 

When you are using the metric SI system of units, it is wise to remember that many units are named in terms of a magnitude of 10, e.g., kilo or mega as a prefix. When you are performing computations, it is advised to reduce these terms to their most basic set of units. For example, if you have a cylinder that is 609.6mm (24") ID that contains 1000KPa of pressure that is 24mm thick, the hoop stress is... 

Multiples and submultiples of SI units are indicated by prefixes, such as milli for 1/1000, centi for 1/100, deci for 1/10, kilo for 1000, and so on. These prefixes are listed inside the cover of this book. We do not use double prefixes such as millikilogram for the gram or microkilogram for the milligram. 

How does adding the prefix kilo- to an SI unit affect the quantity being described ... 

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