Gc (engineering)

In engineering and physics, "g"c is a unit conversion factor used to convert mass to force or vice versa. It is defined as
In unit systems where force is a derived unit, like in SI units, "g"c is equal to 1. In unit systems where force is a primary unit, like in English units, "g"c is not equal to 1, and is required to obtain correct results.
Motivations.
According to Newton's law of motion, the force "F" is proportional to the product of mass "m" and acceleration "a":
or
If "F" = 1 lbf, "m" = 1 lb, and "a" = , then
Leading to
"g"c is defined as the reciprocal of the constant "K"
or equivalently, as