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In the United Kingdom, the ton is a unit of measure which, when it ceased to be legal for trade in 1985, was defined in British legislation as being a weight or mass [sic] equal to 2,240 pounds (1,016 kg) (avoirdupois pounds).[1] In the United States and Canada[2], however, a ton is defined to be 2,000 pounds (907 kg). To avoid confusion, the former is more specifically referred to as a "long ton" and the the latter, a "short ton"; neither should be confused with the metric tonne, which is 1,000 kilograms (2,205 lb). While they do vary, a ton is generally one of the heaviest units of weight or mass referred to in colloquial speech. The term ton is less frequently used to refer to a unit of volume.[citation needed]

Contents

Units of volume

The displacement ton is a unit of volume used for describing the displacement of a ship. It represents the volume of water displaced by the hull. It is usually abbreviated as DT.

One measurement ton is equal to 40 cubic feet. It is sometimes abbreviated as 'MTON'.[3][4][5][6]

The freight ton represents the volume of a truck, train or other freight carrier. In the past it has been used for a cargo ship but the register ton is now preferred. It is equal to 40 cubic feet of space (1.132 cubic metres), but historically it has had several informal definitions. It is correctly abbreviated as 'FT' but some users are now using freight ton to represent a weight of 1 tonne, thus the more common abbreviations are now M/T, MT, or MTON (for measurement ton), which still cause it to be confused with the tonne, or even the megaton.

The register ton is a unit of volume used for the cargo capacity of a ship, defined as 100 cubic feet (roughly 2.83 cubic metres). It is often abbreviated RT or GRT for gross registered ton (The former providing confusion with the refrigeration ton). It is known as a tonneau de mer in Belgium, but, in France, a tonneau de mer is 1.44 cubic metres or about 1.88 cubic yards.

The Panama Canal/Universal Measurement System (PC/UMS) is based on net tonnage, modified for Panama Canal billing purposes. PC/UMS is based on a mathematical formula to calculate a vessel's total volume; a PC/UMS net ton is equivalent to 100 cubic feet of capacity.[7]

The water ton was formerly used in Great Britain and is equal to 224 imperial gallons, the volume occupied by a mass of one long ton under the conditions that define the imperial gallon.

See 1 E-1 m³ and orders of magnitude (volume) for a comparison with other volumes.

(Note that volume tons are units of convenience used in shipping and are not useful in science except that they are exactly defined.)

Units of energy and power

Ton of TNT

  • A ton of TNT or tonne of TNT is a unit of energy equal to 109 (thermochemical) calories, also known as a gigacalorie (Gcal), equal to 4.184 gigajoules (GJ).
  • A kiloton of TNT or kilotonne of TNT is a unit of energy equal to 1012 calories, also known as a teracalorie (Tcal), equal to 4.184 terajoules (TJ).
  • A megaton of TNT (1,000,000 metric tonnes) or megatonne of TNT is a unit of energy equal to 1015 calories, also known (infrequently) as a petacalorie (Pcal), equal to 4.184 petajoules (PJ).

Note that these are small calories (cal). The dietary calorie (Cal) is distinct and equal to one kilocalorie.

Early values for the explosive energy released by trinitrotoluene (TNT) ranged from 900 to 1100 calories per gram. In order to standardise the use of the term TNT as a unit of energy, an arbitrary value was assigned based on 1000 calories (1 kcal, 4.184 kilojoules) per gram. Thus there is no longer a direct connection to the chemical TNT itself. It is now merely a unit of energy that happens to be expressed using words normally associated with mass (e.g., kilogram, tonne, pound).[8][9] The definition applies for both spellings: ton of TNT and tonne of TNT.

Measurements in tons of TNT have been used primarily to express nuclear weapon yields, though they have also been used since in seismology as well.

Ton of coal equivalent

  • A ton of coal equivalent or tonne of coal equivalent (TCE), a conventional value of 7 Gcal (IT) = 29.3076 GJ.

Refrigeration

The unit ton is used in refrigeration and air conditioning to measure heat absorption. Prior to the introduction of mechanical refrigeration, cooling was accomplished by delivering ice. Installing one ton of refrigeration replaced the daily delivery of one ton of ice.

  • In North America, a standard ton of refrigeration is 12,000 BTU/h (3517 W). "The heat absorption per day is approximately the heat of fusion of 1 ton of ice at 32 deg F."[10] This is approximately the power required to melt one short ton (2000 lb) of ice at 0 °C (32 °F) in 24 hours, thus representing the delivery of 1 ton of ice per day.
  • A less common usage is the power required to cool 1 long ton of water by 1 °F every 10 minutes = 13,440 BTU/h ≈ 3939 W.[11][12]

The refrigeration ton is commonly abbreviated as TR.

Truck classes

When light-duty trucks were first produced in the USA, they were rated by their payload capacity in tons (e.g., 12-, 34- and 1-ton). The Ford F-150, Chevy/GMC 1500, and Dodge 1500 are a 12-ton. The Ford F-250, Chevy/GMC 2500, and Dodge 2500 are a 34-ton. The Ford F-350, Chevy/GMC 3500, and Dodge 3500 are a 1-ton.[citation needed] But throughout the years, the payload capacities have increased while the ton title has stayed the same.[citation needed] The current ton rating scheme is just a generic truck name.

Informal tons

  • Ton is also used informally, often as slang, to mean a large amount of something (material or not), for example, "Man, I just ate a ton of french fries back there". It can also be used as a highly derogatory meaning for very overweight persons, e.g., "look at that ten-ton Tess".
  • In Britain, a ton is colloquially used to refer to 100 of a given unit. Ton can thus refer to a speed of 100 miles per hour e.g. "Lee was doing a ton down the motorway"; to money e.g. "How much did you pay for that?" "A ton" (£100); to 100 points in a game e.g. "Eric just threw a ton in our darts game" (in some games, e.g. cricket, more commonly called a century); or to a hundred of pretty much anything else.

See also

References


Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

See also ton, tón, tòn, and -ton

Contents

German

Etymology 1

Old High German dāha

Noun

Ton m. (genitive Tons or Tones, plural Töne)

  1. clay

Etymology 2

Old High German tonus

Noun

Ton m.

  1. tone

Simple English

A ton is a unit of weight or mass. There are three primary varieties of ton:

  • The common ton or short ton, defined as 2 000 pounds avoirdupois (907 kg)
  • The long ton, defined as 2 240 pounds (1 016 kg)
  • The tonne, called a metric ton in the United States, is defined as 1 000 kilograms (2 204 pounds). This unit is also called a "megagram" (1 000 000 g) but "tonne" is more convenient.
krc:Тонна









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