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Ounce-force
The pound of force or pound-force (symbol: lbf, sometimes lbf,) is a unit of force used in some systems of measurement, including English Engineering units and the foot–pound–second system. Pound-force should not be confused with pound-mass (lb), often simply called ''pound'', which is a unit of mass, nor should these be confused with foot-pound (ft⋅lbf), a unit of energy, or pound-foot (lbf⋅ft), a unit of torque. Definitions The pound-force is equal to the gravitational force exerted on a mass of one avoirdupois pound on the surface of Earth. Since the 18th century, the unit has been used in low-precision measurements, for which small changes in Earth's gravity (which varies from equator to pole by up to half a percent) can safely be neglected. The 20th century, however, brought the need for a more precise definition, requiring a standardized value for acceleration due to gravity. Product of avoirdupois pound and standard gravity The pound-force is the produc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
English Engineering Units
Some fields of engineering in the United States use a system of measurement of physical quantities known as the English Engineering Units. Despite its name, the system is based on United States customary units of measure; it is not used in England. A similar system, termed British Engineering Units by Halliday and Resnick (1974), was a system that used the slug as the unit of mass, and in which Newton's law retains the form ''F=ma''. Modern British engineering practice has used SI base units since at least the late 1970s. Definition The English Engineering Units is a system of consistent units used in the United States. The set is defined by the following units, with a comparison of their definitive conversions to their International System of Units counterparts. Units for other physical quantities are derived from this set as needed. In English Engineering Units, the pound-mass and the pound-force are distinct base units, and Newton's Second Law of Motion takes the form ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Yard And Pound
The international yard and pound are two units of measurement that were the subject of an agreement among representatives of six nations signed on 1 July 1959: the United States, United Kingdom, Canada, Australia, New Zealand, and South Africa. The agreement defined the yard as exactly and the avoirdupois pound as exactly . History In October 1834, the United Kingdom Houses of Parliament were destroyed in a fire. Among the items lost were the objects that defined the imperial standards of length and mass. New prototypes were subsequently created to replace the items lost in the fire, among them a new "yardstick" ruler in 1855, and with it a new formal definition of the yard. Two copies of the ruler were subsequently presented to the United States, which in turn adopted the measure for the United States national standard yard. In 1866, the U.S. Congress passed a law that allowed, but did not require, the use of the metric system in trade and commerce. Included in the law was a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kip (unit)
A kip is a US customary unit of force. It equals 1000 pounds-force, and is used primarily by structural engineers to indicate forces where the value represented in pound-force is inefficient. Although uncommon, it is occasionally also considered a unit of mass, equal to 1000 pounds (i.e. one half of a short ton). Another use is as a unit of deadweight to compute shipping charges. :1 kip = 4448.2216 N = 4.4482216 kN The name comes from combining the words ''kilo'' and ''pound''; it is occasionally called a kilopound. Its symbol is kip, sometimes K (upper or lowercase), or less frequently, klb. When it is necessary to clearly distinguish it as a unit of force rather than mass, it is sometimes called the ''kip-force'' (symbol kipf or klbf). The symbol kp usually stands for the ''kilopond'', a unit of force, or kilogram-force, used primarily in Europe prior to the introduction of SI units. The kip is also the name of a unit of mass equal to approximately 9.19 kilograms. Thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ton-force
A ton-force is one of various units of force defined as the weight of one ton due to standard gravity.All calculations on this page assume the following definition of standard gravity, ''g''0. :''g''0 = The precise definition depends on the definition of ''ton'' used. Tonne-force The tonne-force (tf or tf)The tonne-force, also known as the metric ton-force, is equivalent to the megagram-force (Mgf or Mgf) and the megapond (Mp). is equal to the weight of one tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State .... : Long ton-force The long ton-force is equal to the weight of one long ton. : Short ton-force The short ton-force is equal to the weight of one short ton. : Notes {{reflist, group=note Units of force ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foot-pound (energy)
The foot-pound force (symbol: ft⋅lbf, ft⋅lbf, or ft⋅lb ) is a unit of work or energy in the engineering and gravitational systems in United States customary and imperial units of measure. It is the energy transferred upon applying a force of one pound-force (lbf) through a linear displacement of one foot. The corresponding SI unit is the joule. Usage The foot-pound is often used to specify the muzzle energy of a bullet in small arms ballistics, particularly in the United States. The term ''foot-pound'' is also used as a unit of torque (see '' pound-foot (torque)''). In the United States this is often used to specify, for example, the tightness of a fastener (such as screws and nuts) or the output of an engine. Although they are dimensionally equivalent, energy (a scalar) and torque (a Euclidean vector) are distinct physical quantities. Both energy and torque can be expressed as a product of a force vector with a displacement vector (hence pounds and feet); ener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wired
''Wired'' (stylized as ''WIRED'') is a monthly American magazine, published in print and online editions, that focuses on how emerging technologies affect culture, the economy, and politics. Owned by Condé Nast, it is headquartered in San Francisco, California, and has been in publication since March/April 1993. Several spin-offs have been launched, including '' Wired UK'', ''Wired Italia'', ''Wired Japan'', and ''Wired Germany''. From its beginning, the strongest influence on the magazine's editorial outlook came from founding editor and publisher Louis Rossetto. With founding creative director John Plunkett, Rossetto in 1991 assembled a 12-page prototype, nearly all of whose ideas were realized in the magazine's first several issues. In its earliest colophons, ''Wired'' credited Canadian media theorist Marshall McLuhan as its " patron saint". ''Wired'' went on to chronicle the evolution of digital technology and its impact on society. ''Wired'' quickly became recogni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Shuttle Solid Rocket Booster
The Space Shuttle Solid Rocket Booster (SRB) was the first solid-propellant rocket to be used for primary propulsion on a vehicle used for human spaceflight. A pair of these provided 85% of the Space Shuttle's thrust at liftoff and for the first two minutes of ascent. After burnout, they were jettisoned and parachuted into the Atlantic Ocean where they were recovered, examined, refurbished, and reused. The Space Shuttle SRBs were the most powerful solid rocket motors to ever launch humans. The Space Launch System (SLS) SRBs, adapted from the shuttle, surpassed it as the most powerful solid rocket motors ever flown, after the launch of the Artemis-1 mission. Each Space Shuttle SRB provided a maximum thrust, roughly double the most powerful single-combustion chamber liquid-propellant rocket engine ever flown, the Rocketdyne F-1. With a combined mass of about , they comprised over half the mass of the Shuttle stack at liftoff. The motor segments of the SRBs were manufactured by T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Shuttle
The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program name was Space Transportation System (STS), taken from a 1969 plan for a system of reusable spacecraft where it was the only item funded for development. The first ( STS-1) of four orbital test flights occurred in 1981, leading to operational flights (STS-5) beginning in 1982. Five complete Space Shuttle orbiter vehicles were built and flown on a total of 135 missions from 1981 to 2011. They launched from the Kennedy Space Center (KSC) in Florida. Operational missions launched numerous satellites, interplanetary probes, and the Hubble Space Telescope (HST), conducted science experiments in orbit, participated in the Shuttle-''Mir'' program with Russia, and participated in construction and servicing of the International Space Station (IS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gc (engineering)
In engineering and physics, ''g''c is a unit conversion factor used to convert mass to force or vice versa. It is defined as :g_\text = \frac In unit systems where force is a derived unit, like in SI units, ''g''c is equal to 1. In unit systems where force is a primary unit, like in imperial and US customary measurement systems, ''g''c may or may not equal 1 depending on the units used, and value other than 1 may be required to obtain correct results. For example, in the kinetic energy (KE) formula, if ''g''c = 1 is used, then KE is expressed in foot-poundals; but if ''g''c = 32.174 is used, then KE is expressed in foot-pounds. Motivations According to Newton's second law, the force ''F'' is proportional to the product of mass ''m'' and acceleration ''a'': :F \propto ma or :F = K ma If ''F'' = 1 lbf, ''m'' = 1 lb, and ''a'' = , then :1~\text = K \cdot 1~\text \cdot 32.174~\frac Leading to :K = \frac = 0.03108~\frac ''g''c is defined as the reciprocal Reciprocal may refer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newton's Laws Of Motion
Newton's laws of motion are three basic laws of classical mechanics that describe the relationship between the motion of an object and the forces acting on it. These laws can be paraphrased as follows: # A body remains at rest, or in motion at a constant speed in a straight line, unless acted upon by a force. # When a body is acted upon by a force, the time rate of change of its momentum equals the force. # If two bodies exert forces on each other, these forces have the same magnitude but opposite directions. The three laws of motion were first stated by Isaac Newton in his '' Philosophiæ Naturalis Principia Mathematica'' (''Mathematical Principles of Natural Philosophy''), originally published in 1687. Newton used them to investigate and explain the motion of many physical objects and systems, which laid the foundation for classical mechanics. In the time since Newton, the conceptual content of classical physics has been reformulated in alternative ways, involving diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weight
In science and engineering, the weight of an object is the force acting on the object due to gravity. Some standard textbooks define weight as a vector quantity, the gravitational force acting on the object. Others define weight as a scalar quantity, the magnitude of the gravitational force. Yet others define it as the magnitude of the reaction force exerted on a body by mechanisms that counteract the effects of gravity: the weight is the quantity that is measured by, for example, a spring scale. Thus, in a state of free fall, the weight would be zero. In this sense of weight, terrestrial objects can be weightless: ignoring air resistance, the famous apple falling from the tree, on its way to meet the ground near Isaac Newton, would be weightless. The unit of measurement for weight is that of force, which in the International System of Units (SI) is the newton. For example, an object with a mass of one kilogram has a weight of about 9.8 newtons on the surface of the Earth, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slug (unit)
The slug is a derived unit of mass in a weight-based system of measures, most notably within the British Imperial measurement system and the United States customary measures system. Systems of measure either define mass and derive a force unit ''or'' define a base force and derive a mass unit (cf. '' poundal'', a derived unit of force in a force-based system). A slug is defined as the mass that is accelerated by 1 ft/s2 when a net force of one pound (lbf) is exerted on it. : 1~\text = 1~\text\frac \quad\Longleftrightarrow\quad 1~\text = 1~\text\frac One slug is a mass equal to based on standard gravity, the international foot, and the avoirdupois pound.Shigley, Joseph E. and Mischke, Charles R. ''Mechanical Engineering Design'', Sixth ed, pp. 31–33. McGraw Hill, 2001. . At the Earth's surface, an object with a mass of 1 slug weighs approximately .Shevell, R.S. ''Fundamentals of Flight'', Second ed, p. xix. Prentice-Hall, 1989. History The ''slug'' is part of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
