Symbol g. The acceleration experienced by any massive object falling freely in the earth’s gravitational field. Experimentally this is almost constant for all positions near the earth’s surface, independent of the nature of the falling body (provided air resistance is eliminated). This is taken to indicate the strict proportionality of weight (the force causing the acceleration) and inertial mass, on the basis of Newton’s second law of motion. There is some variation of g with latitude, because of the earth’s rotation and because the earth is not completely spherical. The standard value is taken as 9.806 65 m s⁻². The acceleration of free fall is also called the acceleration due to gravity.