The International System of units, abbreviated SI after the
French “Système International d’Unités,” is a modern version of the
metric system which has received worldwide recognition. As shown in
Table 1–1 , the SI system defines length in meters (m), time in seconds (s),
and mass in kilograms (kg). The unit of force, called a newton (N), is
derived from F = ma . Thus, 1 newton is equal to a force required to give
1 kilogram of mass an acceleration of 1 m>s2 (N = kg # m>s2) .
If the weight of a body located at the “standard location” is to be
determined in newtons, then Eq. 1–3 must be applied. Here measurements
give g = 9.806 65 m>s2 ; however, for calculations, the value g = 9.81 m>s2
will be used. Thus,