Force
In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newtons and represented by the symbol F.
Gc (engineering)
In unit systems where force is a derived unit, like in SI units, "g" is equal to 1 and is not needed. In unit systems where force is a primary unit, like in English units, "g" is not equal to 1, and is required to obtain correct results.