Definition [ edit ]
A newton is defined as 1 kg⋅m/s 2 (it is a derived unit which is defined in terms of the SI base units).  One newton is therefore the force needed to accelerate one kilogram of mass at the rate of one metre per second squared in the direction of the applied force.  The units «metre per second squared» can be understood as a change in velocity per time, i.e. an increase of velocity by 1 metre per second every second.
In 1946, Conférence Générale des Poids et Mesures (CGPM) Resolution 2 standardized the unit of force in the MKS system of units to be the amount needed to accelerate 1 kilogram of mass at the rate of 1 metre per second squared. In 1948, the 9th CGPM Resolution 7 adopted the name newton for this force.  The MKS system then became the blueprint for today’s SI system of units. The newton thus became the standard unit of force in the Système international d’unités (SI), or International System of Units.
The newton is named after Isaac Newton. As with every SI unit named for a person, its symbol starts with an upper case letter (N), but when written in full it follows the rules for capitalisation of a common noun; i.e., «newton» becomes capitalised at the beginning of a sentence and in titles, but is otherwise in lower case.
In more formal terms, Newton’s second law of motion states that the force exerted on an object is directly proportional to the acceleration hence acquired by that object, namely: