SI

Rute (rod): Carolingian origin, use as land measure. e.g. - Saxony (Sachsen) : 1 alte Rute = 1 Feldmesser-Rute = 7.5 Ellen = 4.295 m - Saxony (Sachsen) : 1 neue Straßen-Rute = 16 Fuß (feet) = 4.531 m - Rhineland (Rheinland) + Prussia (Preußen) : 1 Rheinische Rute = 12 Fuß (feet) = 3.766 m - Bavaria (Bayern) : 1 Rute = 10 Fuß (feet) = 2.919 m - Baden + Switzerland: 1 Rute = 10 Fuß (feet) = 3 m - Sweden : 1 Rute = 16 Fot (feet) = 4.749 mSee also:

German units of measurement, German units of measurement - German system, German units of measurement - Length, German units of measurement - Volume

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The letter A is the first letter in the Latin alphabet. Its name in English is a, plural ās or aes. A - History. The letter A probably started as a pictogram of an ox head in Egyptian hieroglyphs or the Proto-semitic alphabet. By 1600 BC, the Phoenician alphabet's letter had a linear form that served as the basis for all later forms. Its name must have corresponded closely to the Hebrew aleph. The name is also similar to the Arabic alif. When the Ancient Greeks ad ...

Including:

• A - A
• A - History
• A - Usage
• A - Alternative representations
• A - Meanings for A

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Because it is a base unit, the definition of the ampere is not tied to any other electrical unit. The definition for the ampere is equivalent to fixing a value of the permeability of vacuum to μ0 = 4π×10−7 H/m. Prior to 1948, the so-called "international ampere" was used, defined in terms of the electrolytic deposition rate of silver. The older unit is equal to 0.999 85 A. The ampere is most accurately realised using an ampere balance, but is in practice maintained via Ohm's Law from the uni ...

See also:

Ampere, Ampere - Definition, Ampere - Explanation

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In physics, acceleration (symbol: a) is defined as the rate of change (or time derivative) of velocity. It is thus a vector quantity with dimension length/time². In SI units, this is metre/second². Acceleration - Explanation. To accelerate an object is to change its velocity in relation to time. In this strict scientific sense, acceleration can have positive and negative values – respectively called acceleration (velocity is increased) and deceleration (or retardation -- velocity is decrea ...

Including:

• Acceleration - Explanation
• Acceleration - Relation to relativity

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There have historically been four different English systems of mass: Tower weight, Troy weight, Avoirdupois system, and Apothecaries' system. Tower weight fell out of use (due to legal prohibition) centuries ago, and was never used in the United States. Troy weight is still used to weigh precious metals. Apothecaries weight, once used in pharmacy, has been largely replaced by metric measurements. Avoirdupois weight is th ...

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U.S. customary units, U.S. customary units - Units of length, U.S. customary units - Units of area, U.S. customary units - Units of capacity and volume, U.S. customary units - Volume in general, U.S. customary units - Liquid volume, U.S. customary units - Dry volume, U.S. customary units - Units of mass, U.S. customary units - Avoirdupois weight, U.S. customary units - Apothecaries' weight, U.S. customary units - Troy weight, U.S. customary units - Cooking measures, U.S. customary units - Grain measures, U.S. customary units - Units of temperature, U.S. customary units - Other units

Read more here: » U.S. customary units: Encyclopedia II - U.S. customary units - Units of mass

The Imperial gallon (4.546 09 litres (L)) and bushel (36.368 72 L) are, respectively, about 20 per cent and 3 per cent larger than the United States liquid gallon (3.785 411 784 L) and bushel (35.239 070 166 88 L). The Imperial gallon was originally defined as the volume of 10 avoirdupois pounds of water under specified conditions, and the Imperial bushel was defined as 8 Imperial gallons. Also, the subdivision of the Imperial gallon as presented in the table of British apothecaries' fluid measure differed in two important respects from the ...

See also:

Comparison of the Imperial and U.S. customary systems, Comparison of the Imperial and U.S. customary systems - Volume, Comparison of the Imperial and U.S. customary systems - Length, Comparison of the Imperial and U.S. customary systems - Weight

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A change in temperature of 1°C is equal to a change in temperature of 1K. Temperature in °C = Temperature in kelvins - 273.15 Thus, one could think of the Kelvin scale as the same as the Celsius scale, with its zero point moved down to absolute zero. This perspecitive is historically accurate; however, it has become more convenient to fix the standard for the kelvin, and thus the Celsius scale is derived from that standard (i.e., it now depends on absolute zero and the triple point of water with a 0.01 K offset — the boiling point of wa ...

See also:

SI derived unit, SI derived unit - Dimensionless derived units, SI derived unit - Derived units with special names, SI derived unit - Other quantities and units, SI derived unit - Conversion between kelvins and degrees Celsius

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An angstrom, angström, or ångström (symbol Å) is a unit of length. It is not an SI unit. It is accepted (although discouraged) for use with the SI. It is sometimes used for expressing the sizes of atoms, lengths of chemical bonds and with visible-light spectra. Angstrom - Definition. 1 ångström (Å) = 10–10 metres = 0.1 nm Conversion of units, 1 E-10 m Angstrom - Origin. Including:

• Angstrom - Definition
• Angstrom - Origin
• Angstrom - Writing the characters

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The coulomb is also the unit of electric flux. (See Gauss Law). The coulomb could in principle be defined in terms of the charge of an electron or elementary charge. Since the values of the Josephson (CIPM (1988) Recommendation 1, PV 56; 19) and von Klitzing (CIPM (1988), Recommendation 2, PV 56; 20) constants have been given conventional values (KJ ≡ 4.835 979×1014 Hz/V and RK ≡ 2.5812807×104 Ω), it is possible to combine these values to form an alternative (not yet official) definit ...

See also:

Coulomb, Coulomb - Definition, Coulomb - Explanation, Coulomb - SI multiples, Coulomb - Conversions

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In physics models, the point-like system is used, where objects are represented as one-dimensional points at their centre of mass. The only change the system can experience is a change of its momentum (its velocity). Since the rise of the atomic theory, any physical system has been considered in classical physics as composed of point-like systems called atoms or molecules. Therefore, all forces can be defined by their effect; that is, by the change of movement they induce on point-like systems. This change of movement can be quantifie ...

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Force, Force - Elementary concepts, Force - Quantitative definition, Force - Types of force, Force - Properties of force, Force - Forces in theory, Force - Units of measurement, Force - Non-SI units of force and mass, Force - Conversions, Force - Forces in everyday life, Force - Forces in the laboratory, Force - Founding experiments, Force - Instruments to measure forces, Force - History

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The simplest way to convert from one unit to another is to carry through the units themselves in the mathematical operation. To illustrate this process, consider the following examples. You would like to convert 6 feet into metres. Consulting the table below and finding that one foot is exactly 0.3048 metre, you can now perform the mathematical conversion: Notice that the "foot" units canceled out, leaving only metres, the desired result. (Since 0.3048 metre per foot have infinite precision, the precision of the answer is deter ...

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Conversion of units, Conversion of units - Conversion techniques, Conversion of units - Rounding of results, Conversion of units - Tables of conversion factors, Conversion of units - Length, Conversion of units - Area, Conversion of units - Volume, Conversion of units - Angle, Conversion of units - Mass, Conversion of units - Time, Conversion of units - Speed, Conversion of units - Acceleration, Conversion of units - Force, Conversion of units - Pressure, Conversion of units - Energy or work, Conversion of units - Power, Conversion of units - Angular momentum, Conversion of units - Electric current, Conversion of units - Electric charge, Conversion of units - Electromotive force, Conversion of units - Electrical resistance, Conversion of units - Dynamic viscosity, Conversion of units - Kinematic viscosity, Conversion of units - Temperature

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Metric systems of units have evolved since the adoption of the first well-defined system in France in 1791. During this evolution the use of these systems spread throughout the world, first to the non-English-speaking countries, and more recently to the English speaking countries. Multiples and submultiples of metric units are related by powers of ten; the names for these are formed with prefixes. This relationship is compatible with the decimal system of numbers an ...

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Systems of measurement, Systems of measurement - The metric system, Systems of measurement - Imperial and US customary units, Systems of measurement - Natural units, Systems of measurement - Atomic units, Systems of measurement - Non-standard units, Systems of measurement - Units of currency, Systems of measurement - Historical Mediterranean and European systems of measurement, Systems of measurement - Ancient systems of measurement, Systems of measurement - Mediæval measurements, Systems of measurement - The Chinese system, Systems of measurement - Other historical systems of measurement

Read more here: » Systems of measurement: Encyclopedia II - Systems of measurement - The metric system

Because it is a base unit, the definition of the ampere is not tied to any other electrical unit. The definition for the ampere is equivalent to fixing a value of the permeability of vacuum to μ0 = 4π×10−7 H/m. Prior to 1948, the so-called "international ampere" was used, defined in terms of the electrolytic deposition rate of silver. The older unit is equal to 0.999 85 A. The ampere is most accurately realised using an ampere balance, but is in practice maintained via Ohm's Law from the uni ...

See also:

Ampere, Ampere - Definition, Ampere - Explanation, Ampere - External link

Read more here: » Ampere: Encyclopedia II - Ampere - Explanation

The word metre is from the Greek metron (μετρον), "a measure" via the French mètre. Its first recorded usage in English is from 1797. In the 18th century, there were two favoured approaches to the definition of the standard unit of length. One suggested defining the metre as the length of a pendulum with a half-period of one second. The other suggested defining the metre as one ten-millionth of the length of the earth's meridian along a quadrant (one-fourth the polar circumference of the earth). In 1791, th ...

See also:

Metre, Metre - SI prefixes applied to the metre, Metre - Conversions, Metre - History, Metre - Timeline of definition

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History of measurement - Units of length. The Indus Valley units of length referred to above and the Mesopotamian cubit were both used in the 3rd millennium BC and are the earliest known units used by ancient peoples to measure length. There were several cubits of different magnitudes that were used. The common cubit was the length of the forearm from the elbow to the tip of the middle finger. It was divided into the span of the hand (one-half cubit), the palm or width of the hand (one sixth), and the digi ...

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History of measurement, History of measurement - Introduction, History of measurement - History of units, History of measurement - Units of length, History of measurement - Typographical units, History of measurement - Units of mass, History of measurement - Units of time and angle

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A watt is a unit of power or the amount of energy per unit time. Watt - Kilowatt-hour MWd. When paired with a unit of time the term watt is used for expressing energy consumption. For example, a kilowatt hour, is the amount of energy expended by a one kilowatt device over the course of one hour; it equals 3.6 megajoules (1 hour = 3600 seconds). A megawatt day (MWd or MW·d) is equal to 86.4 GJ (1 day = 86400 seconds). These units are often used in the context of power plants and home energy bills. For the use of watts as a measurement of ...

See also:

Watt, Watt - Definition, Watt - Origin, Watt - SI multiples, Watt - Conversions, Watt - Derived and qualified units for power distribution, Watt - Kilowatt-hour MWd, Watt - MWe MWt

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1 km² is equal to: the area of a square measuring 1 kilometre on each side 1,000,000 m² 100 hectares 0.386 102 square miles (statute) 247.105 381 acres Conversely: 1 m² = 0.000 001 km² 1 hectare = 0.01 km² 1 square mile = 2.589 988 km² 1 acre = 0.004 047 km² Note: "km²" means square kilometre and not kilo–square metre. For example, 3 km� ...

See also:

Square metre, Square metre - Square kilometre, Square metre - Square megametre

Read more here: » Square metre: Encyclopedia II - Square metre - Square kilometre

Like the kilometre, all units of length in the metric system are based on the metre, by adding an SI prefix that stands for a power of ten, such as hecto for one hundred to form hectometre (= 0.1 kilometre) or mega for one million to form megametre (= 1,000 kilometre). The metre is not only the basis for all units of length in the metric system, but also of units of area (the square met ...

See also:

Kilometre, Kilometre - Metric system, Kilometre - Pronunciation

Read more here: » Kilometre: Encyclopedia II - Kilometre - Metric system

English unit - Length. poppyseed  ¼ of a barleycorn barleycorn  Basic Anglo-Saxon unit, the length of a corn of barley. The unit survived after 1066, redefined as 1/3 inch. Note the relation to the grain unit of weight. digit  ¾ inch finger  7/8 inch ynch, inch  Anglo Saxon inch, 3 barleycorns. Based on the Roman uncia from 1066. nail  3 digits = 2¼ inches ...

See also:

English unit, English unit - Historical English units, English unit - Length, English unit - Area, English unit - Administrative units, English unit - Volume, English unit - Weight

Read more here: » English unit: Encyclopedia II - English unit - Historical English units

The kilogram was originally defined as the mass of one litre of pure water at a temperature of 3.98 degrees Celsius and standard atmospheric pressure. This definition was hard to realize accurately, partially because the density of water depends ever-so-slightly on the pressure, and pressure units include mass as a factor, introducing a circular dependency in the definition of the kilogram. To avoid these problems, the kilogram was redefined as precisely the mass of a particular standard mass created to approximate the o ...

See also:

Kilogram, Kilogram - History, Kilogram - The gram, Kilogram - Proposed future definitions, Kilogram - Atom-counting approaches, Kilogram - Fundamental-constant approaches, Kilogram - Link with weight, Kilogram - Examples, Kilogram - SI multiples

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An architect's scale is a specialized ruler. It is used in making or measuring from reduced scale drawings, such as blueprints. It is marked with a range of calibrated scales (ratios). The scale was traditionally made of wood but for accuracy and longevity the material used should be dimensionally stable and durable. Today they are now more commonly made of rigid plastic or aluminium. Depending on the number of different scales to be accommodated architect's scales may be flat or ...

Including:

• Architect's scale - United States and Imperial units
• Architect's scale - Metric units

Read more here: » Architect's scale: Encyclopedia - Architect's scale