Search results
Results From The WOW.Com Content Network
Systems of measure either define mass and derive a force unit or define a base force and derive a mass unit [1] (cf. poundal, a derived unit of force in a mass-based system). A slug is defined as a mass that is accelerated by 1 ft/s 2 when a net force of one pound (lbf) is exerted on it.
This is convenient because one pound mass exerts one pound force due to gravity. Note, however, unlike the other systems the force unit is not equal to the mass unit multiplied by the acceleration unit [11] —the use of Newton's second law, F = m ⋅ a, requires another factor, g c, usually taken to be 32.174049 (lb⋅ft)/(lbf⋅s 2).
The slug is defined as the amount of mass that accelerates at 1 ft/s 2 when one pound-force is exerted on it, and is equivalent to about 32.2 pounds (mass). The kilogram-force is a non-SI unit of force, defined as the force exerted by a one-kilogram mass in standard Earth gravity (equal to 9.80665 newtons exactly).
Force necessary to synchronize the motion of a single trapped ion with an external signal measured in a 2010 experiment [2] [3] 10 −22: 170 yN Force measured in a 2010 experiment by perturbing 60 beryllium-9 ions [4] [5] 10 −18 attonewton (aN) 10 −17: 30 aN Smallest force of gravity measured [6] [7] 10 −15 femtonewton (fN) 10 −14 ~10 fN
Together with the fact that the term "weight" is used for the gravitational force in some technical contexts (physics, engineering) and for mass in others (commerce, law), [10] and that the distinction often does not matter in practice, the coexistence of variants of the FPS system causes confusion over the nature of the unit "pound".
In scientific contexts, mass is the amount of "matter" in an object (though "matter" may be difficult to define), but weight is the force exerted on an object's matter by gravity. [1] At the Earth 's surface, an object whose mass is exactly one kilogram weighs approximately 9.81 newtons , the product of its mass and the gravitational field ...
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 ).
The weight of an object on Earth's surface is the downwards force on that object, given by Newton's second law of motion, or F = m a (force = mass × acceleration). Gravitational acceleration contributes to the total gravity acceleration, but other factors, such as the rotation of Earth, also contribute, and, therefore, affect the weight of the ...