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# fundamental and derived quantities and units of measurement

From Wikipedia

Derivative

In calculus, a branch of mathematics, the derivative is a measure of how a function changes as its input changes. Loosely speaking, a derivative can be thought of as how much one quantity is changing in response to changes in some other quantity; for example, the derivative of the position

From Encyclopedia

English units of measurement

English units of measurement principal system of weights and measures used in a few nations, the only major industrial one being the United States. It actually consists of two related systemsâ€”the U.S. Customary System of units, used in the United States and dependencies, and the British Imperial System. The names of the units and the relationships between them are generally the same in both systems, but the sizes of the units differ, sometimes considerably. Customary Units of Weights and Measures Units of Weight The pound (lb) is the basic unit of weight (which is proportional to mass). Within the English units of measurement there are three different systems of weights. In the avoirdupois system, the most widely used of the three, the pound is divided into 16 ounces (oz) and the ounce into 16 drams. The ton, used to measure large masses, is equal to 2,000 lb (short ton) or 2,240 lb (long ton). In Great Britain the stone, equal to 14 lb, is also used. The troy system (named for Troyes, France, where it is said to have originated) is used only for precious metals. The troy pound is divided into 12 ounces and the troy ounce into 20 pennyweights or 480 grains; the troy pound is thus 5,760 grains. The grain is also a unit in the avoirdupois system, 1 avoirdupois pound being 7,000 grains, so that the troy pound is 5,760/7,000 of an avoirdupois pound. Apothecaries' weights are based on troy weights; in addition to the pound, ounce, and grain, which are equal to the troy units of the same name, other units are the dram (1/8 oz) and the scruple (1/24 oz or 1/3 dram). Units of Length and Area The basic unit of length is the yard (yd); fractions of the yard are the inch (1/36 yd) and the foot (1/3 yd), and commonly used multiples are the rod (5 1/2 yd), the furlong (220 yd), and the mile (1,760 yd). The acre, equal to 4,840 square yards or 160 square rods, is used for measuring land area. Units of Liquid Measure For liquid measure, or liquid capacity, the basic unit is the gallon, which is divided into 4 quarts, 8 pints, or 32 gills. The U.S. gallon, or wine gallon, is 231 cubic inches (cu in.); the British imperial gallon is the volume of 10 lb of pure water at 62Â°F and is equal to 277.42 cu in. The British units of liquid capacity are thus about 20% larger than the corresponding American units. The U.S. fluid ounce is 1/16 of a U.S. pint; the British unit of the same name is 1/20 of an imperial pint and is thus slightly smaller than the U.S. fluid ounce. Units of Dry Measure For dry measure, or dry capacity, the basic unit is the bushel, which is divided into 4 pecks, 32 dry quarts, or 64 dry pints. The U.S. bushel, or Winchester bushel, is 2,150.42 cu in. and is about 3% smaller than the British imperial bushel of 2,219.36 cu in., with a similar difference existing between U.S. and British subdivisions. The barrel is a unit for measuring the capacity of larger quantities and has various legal definitions depending on the quantity being measured, the most common value being 105 dry quarts. Differences between American and British Systems Many American units of weights and measures are based on units in use in Great Britain before 1824, when the British Imperial System was established. Since the Mendenhall Order of 1893, the U.S. yard and pound and all other units derived from them have been defined in terms of the metric units of length and mass, the meter and the kilogram ; thus, there is no longer any direct relationship between American units and British units of the same name. In 1959 an international agreement was reached among English-speaking nations to use the same metric equivalents for the yard and pound for purposes of science and technology; these values are 1 yd=0.9144 meter (m) and 1 lb=0.45359237 kilogram (kg). In the United States, the older definition of the yard as 3,600/3,937 m is still used for surveying, the corresponding foot (1,200/3,937 m) being known as the survey foot. The English units of measurement have many drawbacks: the complexity of converting from one unit to another, the differences between American and British units, the use of the same name for different units (e.g., ounce for both weight and liquid capacity, quart and pint for both liquid and dry capacity), and the existence of three different systems of weights (avoirdupois, troy, and apothecaries'). Because of these disadvantages and because of the wide use of the much simpler metric system in most other parts of the world, there have been proposals to do away with the U.S. Customary System and replace it with the metric system. Bibliography See L. J. Chisholm, Units of Weights and Measure: International and U.S. Customary (U.S. National Bureau of Standards, 1967).

Particles, Fundamental Particles, Fundamental

Question:please help me....because of this question my first day of school got to be very embarrass...i couldn't even answer this question and my teacher gave this to me as my homework...huhuhuhuhuhuhu T^T thank you for those people who will answer this question...mwah!!

Answers:Here are the seven fundamental quantities. I also included their definitions and SI units. length - meter (m) - the measurement or extent of something from end to end. mass - kilogram (kg) - a coherent body of matter with no definite shape. time - second (s) - the indefinite continued progress of existence and events. electric current - ampere (A) - flow of electric charge. thermodynamic temperature - kelvin (K) - A measure proportional to the thermal energy of a given body at equilibrium. amount of substance - mole (mol) - the number of specified group of entities present in a substance. luminous intensity - candela (cd) - an expression of the amount of light power emanating from a point source within a solid angle of one steradian.

Question:What is the difference between a fundamental physical quantity and a standard unit.

Answers:A fundamental physical quantity is an actual measurable quantity, for example: speed of light, weight of an electron, charge of an electron. A Standard unit is a defined measurement unit like a meter, or a gram.

Question:can any one list out the 7 fundamental Qs 4me, thanx...

Answers:(I)fundamental units: those units which are the quantities which are independent of each other. All other quantities may be expressed in these units. It turns out that the number of fundamental units is 7. They are: (a)length (metre; m) (b)mass (kilogram, kg) (c)time (second, s) (d)luminous intensity (candela, cd) (e)electric intensity (ampere, A) (f)amount of substance (mole, mol) (g)thermodynamic temperature (Kelvin, K)

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