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[[Coadan:Force.png|right|300 px|thumb|Dy cadjin, t'ad soilshaghey forseyn myr seiy ny tayrn. Foddee ad gobbraghey liorish [[trimmid]], [[magnaidys]] as [[phenomenon|phenomena]] elley ta cur er nhee siyraghey.]]

She parameter vaghtooragh eh '''forse''', as ta paart mooar echey ayns [[obbrinaght chlassicagh]]. Foddee eh [[bieauaghey]] ny [[aachummey]] nheeghyn, as trooid eiyrtys 'orse, foddee oo jannoo [[obbyr (fishag)|obbyr]] ny caghlaa [[bree]] nhee ennagh. Ta [[mooadys (maddaght)|mooadys]] as [[troa (maddaght)|troa]] ec forse, as myr shen, she [[vaghtoor]] t'ayn.

Ren ny shenn [[fallsoonys|'allsoonee]] ymmyd jeh'n eie dy row forse ayn er son studeyrys er nheeghyn [[obbrinaght staddagh|staddagh]] as [[dynamickyn|gleashagh]]. Ren [[Aristotle]] ymmyd yn eie shen y veenaghey, agh va'n eie echey goaill stiagh far-hoiggalyn bunneydagh v'ayn foast rish ymmodee keeadyn. Haink [[Archimedes]] dy hoiggal eh ny share liorish cooilleeiney [[jeshaght bunneydagh|jeshaghtyn bunneydagh]], agh ec y traa shen, shimmey peiagh va credjue eieyn Aristotle foast.<ref name="Archimedes">{{enmyseddyrvoggyl

== Imraaghyn ==

remains valid due to the fact that it is a mathematical definition.<ref name="Cutnell_p855-876">{{cite book| last =Cutnell| title =Physics, Sixth Edition| pages =855&ndash;876855–876| isbn =047123124X| author =Cutnell,| publisher =John Wiley & Sons Inc}}</ref> But in order to be conserved, relativistic momentum must be redefined as:

Newton's contribution to gravitational theory was to unify the motions of heavenly bodies, which Aristotle had assumed were in a natural state of constant motion, with falling motion observed on the Earth. He proposed a [[Newton's Law of Gravity|law of gravity]] that could account for the celestial motions that had been described earlier using [[Kepler's Laws of Planetary Motion]].<ref name=uniphysics_ch4>''University Physics'', Sears, Young & Zemansky, pp59&ndash;82pp59–82</ref>

Since then, and so far, general relativity has been acknowledged as the theory which best explains gravity. In GR, gravitation is not viewed as a force, but rather, objects moving freely in gravitational fields travel under their own inertia in [[geodesic|straight lines]] through [[curved space-time]] &ndash;– defined as the shortest space-time path between two space-time events. From the perspective of the object, all motion occurs as if there were no gravitation whatsoever. It is only when observing the motion in a global sense that the curvature of space-time can be observed and the force is inferred from the object's curved path. Thus, the straight line path in space-time is seen as a curved line in space, and it is called the ''[[external ballistics|ballistic]] [[trajectory]]'' of the object. For example, a [[basketball]] thrown from the ground moves in a [[parabola]], as it is in a uniform gravitational field. Its space-time trajectory (when the extra ct dimension is added) is almost a straight line, slightly curved (with the [[radius of curvature (applications)|radius of curvature]] of the order of few [[light-year]]s). The time derivative of the changing momentum of the object is what we label as "gravitational force".<ref name="texts" />

|pages=364&ndash;383364–383

The [[SI]] unit of force is the [[Newton (unit)|newton]] (symbol N), which is the force required to accelerate a one kilogram mass at a rate of one meter per second squared, or kg·m·s^&minus;2−2.<ref name=metric_units>

{{cite book |first=Cornelius |last=Wandmacher |first2=Arnold |last2=Johnson |title=Metric Units in Engineering |page=15 |year=1995 |publisher=ASCE Publications |isbn=0784400709}}</ref> The corresponding [[CGS]] unit is the [[dyne]], the force required to accelerate a one gram mass by one centimeter per second squared, or g·cm·s^&minus;2−2. A newton is thus equal to 100,000&nbsp;dyne.

The gravitational [[foot-pound-second]] [[English unit]] of force is the [[pound-force]] (lbf), defined as the force exerted by gravity on a [[pound-mass]] in the [[Standard gravity|standard gravitational]] field of 9.80665&nbsp;m·s^&minus;2−2.<ref name=metric_units/> The pound-force provides an alternative unit of mass: one [[slug (mass)|slug]] is the mass that will accelerate by one foot per second squared when acted on by one pound-force.<ref name=metric_units/>

The pound-force has a metric counterpart, less commonly used than the newton: the [[kilogram-force]] (kgf) (sometimes [[kilopond]]), is the force exerted by standard gravity on one kilogram of mass.<ref name=metric_units/> The kilogram-force leads to an alternate, but rarely used unit of mass: the [[metric slug]] (sometimes [[mug]] or [[hyl]]) is that mass which accelerates at 1&nbsp;m·s^&minus;2−2 when subjected to a force of 1&nbsp;kgf. The kilogram-force is not a part of the modern SI system, and is generally deprecated; however it still sees use for some purposes as expressing jet thrust, bicycle spoke tension, torque wrench settings and engine output torque. Other arcane units of force include the [[sthène]] which is equivalent to 1000&nbsp;N and the [[kip (force)|kip]] which is equivalent to 1000&nbsp;lbf.

[[ckb:هێزھێز (فیزیک)]]