The figure "9.8 m/s squared" is the constant for the acceleration of a free falling object in a vacuum, or gravitational acceleration. An object is considered "free falling" when its motion is attributable to the force of gravity alone.
The figure is formally written as: "g = 9.8(m/s)squared," where the "m/s" stands for "meters per second" and "g" represents "gravity." The change in speed of an object is calculated by using Newton's second law of motion. An object's velocity is calculated with the formula "V = a * t" in which "V" is "velocity," "a" is the object's acceleration and "t" is the time.