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Newton Meters
The newton-metre (also newton metre or newton meter; symbol N⋅m or N m) is the unit of torque (also called ) in the International System of Units (SI). One newton-metre is equal to the torque resulting from a force of one newton applied perpendicularly to the end of a moment arm that is one metre long. The nonstandard notation ''Nm'' occurs in some fields. The unit is also used less commonly as a unit of work, or energy, in which case it is equivalent to the more common and standard SI unit of energy, the joule.For example: Eshbach's handbook of engineering fundamentals - 10.4 Engineering Thermodynamics and Heat Transfer "In SI units the basic unit of energy is newton-metre". In this usage the metre term represents the distance travelled or displacement in the direction of the force, and not the perpendicular distance from a fulcrum as it does when used to express torque. This usage is generally discouraged, since it can lead to confusion as to whether a given quantity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torque
In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of the body. The concept originated with the studies by Archimedes of the usage of levers, which is reflected in his famous quote: "''Give me a lever and a place to stand and I will move the Earth''". Just as a linear force is a push or a pull, a torque can be thought of as a twist to an object around a specific axis. Torque is defined as the product of the magnitude of the perpendicular component of the force and the distance of the line of action of a force from the point around which it is being determined. The law of conservation of energy can also be used to understand torque. The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. When being referred to as moment of force, it is commonly denoted by . In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SI Base Unit
The SI base units are the standard units of measurement defined by the International System of Units (SI) for the seven base quantities of what is now known as the International System of Quantities: they are notably a basic set from which all other SI units can be derived. The units and their physical quantities are the second for time, the metre (sometimes spelled meter) for length or distance, the kilogram for mass, the ampere for electric current, the kelvin for thermodynamic temperature, the mole for amount of substance, and the candela for luminous intensity. The SI base units are a fundamental part of modern metrology, and thus part of the foundation of modern science and technology. The SI base units form a set of mutually independent dimensions as required by dimensional analysis commonly employed in science and technology. The names and symbols of SI base units are written in lowercase, except the symbols of those named after a person, which are written with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torque Tester
A torque tester is used as a quality control device to test or calibrate torque controlled tools. This includes electronic torque wrenches, click torque wrenches, dial torque wrenches, electric screwdrivers, air screwdrivers, pulse tools, cordless screwdrivers, nutrunners, and torque screwdrivers. Today's advanced torque testers include the ability to measure in clockwise and counter-clockwise directions, and potentially convert to engineering units (such as in·oz, in·lb, ft·lb, N·m, cN·m, kgf·cm, gf·cm, kgf·fm). They can also have different modes of operation (such as peak, 1st peak, track), or include a certificate from a local regulator (such as NIST). Torque testers measure properties such as torsional strength and stiffness and are used in quality control of various fields including medical devices, metals, and aerospace. Components Transducer A torque transducer, similar to a load cell, is an electronic device used to convert torque into an electrical signal. This co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spring Scale
A spring scale, spring balance or newton meter is a type of mechanical force gauge or weighing scale. It consists of a spring fixed at one end with a hook to attach an object at the other. It works in accordance with Hooke's Law, which states that the force needed to extend or compress a spring by some distance scales linearly with respect to that distance. Therefore, the scale markings on the spring balance are equally spaced. A spring balance can be calibrated for the accurate measurement of mass in the location in which they are used, but many spring balances are marked right on their face "Not Legal for Trade" or words of similar import due to the approximate nature of the theory used to mark the scale. Also, the spring in the scale can permanently stretch with repeated use. A spring scale will only read correctly in a frame of reference where the acceleration in the spring axis is constant (such as on earth, where the acceleration is due to gravity). This can be shown by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bending Moment
In solid mechanics, a bending moment is the reaction induced in a structural element when an external force or moment is applied to the element, causing the element to bend. The most common or simplest structural element subjected to bending moments is the beam. The diagram shows a beam which is simply supported (free to rotate and therefore lacking bending moments) at both ends; the ends can only react to the shear loads. Other beams can have both ends fixed (known as encastre beam); therefore each end support has both bending moments and shear reaction loads. Beams can also have one end fixed and one end simply supported. The simplest type of beam is the cantilever, which is fixed at one end and is free at the other end (neither simple or fixed). In reality, beam supports are usually neither absolutely fixed nor absolutely rotating freely. The internal reaction loads in a cross-section of the structural element can be resolved into a resultant force and a resultant couple. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dyne
The dyne (symbol: dyn; ) is a derived unit of force specified in the centimetre–gram–second (CGS) system of units, a predecessor of the modern SI. History The name dyne was first proposed as a CGS unit of force in 1873 by a Committee of the British Association for the Advancement of Science. Definition The dyne is defined as "the force required to accelerate a mass of one gram at a rate of one centimetre per second squared". An equivalent definition of the dyne is "that force which, acting for one second, will produce a change of velocity of one centimetre per second in a mass of one gram". One dyne is equal to 10 micronewtons, 10−5 N or to 10 nsn (nano sthenes) in the old metre–tonne–second system of units. : 1 dyn = 1 g⋅cm/s2 = 10−5 kg⋅m/s2 = 10−5 N : 1 N = 1 kg⋅m/s2 = 105 g⋅cm/s2 = 105 dyn Use The dyne per centimetre is a unit traditionally used to measure surface tension. For example, the surface tension of distilled water is 71.99 dyn/c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pound (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 product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pound (mass)
The pound or pound-mass is a unit of mass used in British imperial and United States customary systems of measurement. Various definitions have been used; the most common today is the international avoirdupois pound, which is legally defined as exactly , and which is divided into 16 avoirdupois ounces. The international standard symbol for the avoirdupois pound is lb; an alternative symbol is lbm (for most pound definitions), # ( chiefly in the U.S.), and or ″̶ (specifically for the apothecaries' pound). The unit is descended from the Roman (hence the abbreviation "lb"). The English word ''pound'' is cognate with, among others, German , Dutch , and Swedish . These units are historic and are no longer used (replaced by the metric system). Usage of the unqualified term ''pound'' reflects the historical conflation of mass and weight. This accounts for the modern distinguishing terms ''pound-mass'' and '' pound-force''. Etymology The word 'pound' and its cognates ultim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pound (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 product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Gravity
The standard acceleration due to gravity (or standard acceleration of free fall), sometimes abbreviated as standard gravity, usually denoted by or , is the nominal gravitational acceleration of an object in a vacuum near the surface of the Earth. It is defined by standard as . This value was established by the 3rd CGPM (1901, CR 70) and used to define the standard weight of an object as the product of its mass and this nominal acceleration. The acceleration of a body near the surface of the Earth is due to the combined effects of gravity and centrifugal acceleration from the rotation of the Earth (but the latter is small enough to be negligible for most purposes); the total (the apparent gravity) is about 0.5% greater at the poles than at the Equator. Although the symbol is sometimes used for standard gravity, (without a suffix) can also mean the local acceleration due to local gravity and centrifugal acceleration, which varies depending on one's position on Earth (see Earth's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilogram-force
The kilogram-force (kgf or kgF), or kilopond (kp, from la, pondus, lit=weight), is a non-standard gravitational metric unit of force. It does not comply with the International System of Units (SI) and is deprecated for most uses. The kilogram-force is equal to the magnitude of the force exerted on one kilogram of mass in a gravitational field (standard gravity, a conventional value approximating the average magnitude of gravity on Earth). That is, it is the weight of a kilogram under standard gravity. Therefore, one kilogram-force is by definition equal to .NISTbr>''Guide for the Use of the International System of Units (SI)''Special Publication 811, (1995) page 51 Similarly, a gram-force is , and a milligram-force is . Kilogram-force is a non-standard unit and is classified in the International System of Units (SI) as a unit that is not accepted for use with SI. History The gram-force and kilogram-force were never well-defined units until the CGPM adopted a ''standard accele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sheet Resistance
Sheet resistance, is a measure of resistance of thin films that are uniform in thickness. It is commonly used to characterize materials made by semiconductor doping, metal deposition, resistive paste printing, and glass coating. Examples of these processes are: doped semiconductor regions (e.g., silicon or polysilicon), and the resistors that are screen printed onto the substrates of thick-film hybrid microcircuits. The utility of sheet resistance as opposed to resistance or resistivity is that it is directly measured using a four-terminal sensing measurement (also known as a four-point probe measurement) or indirectly by using a non-contact eddy-current-based testing device. Sheet resistance is invariable under scaling of the film contact and therefore can be used to compare the electrical properties of devices that are significantly different in size. Calculations Sheet resistance is applicable to two-dimensional systems in which thin films are considered two-dimensional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
