Why acceleration due to gravity is independent of size, shape and mass?

                                

  Acceleration due to gravity is an acceleration which is produced by gravitational pull of earth in a free falling body. Acceleration due to gravity is also known as Acceleration of freely falling body . We have formula of acceleration due to gravity is;  g=GMe/Re2.

Acceleration due to gravity just depends on  M= mass of earth , Re= distance of object from centre of earth. So it shows that acceleration due to gravity is independent of mass, shape and size of object. It does not matter how heavy object is. All objects falling freely will face same acceleration. But acceleration of an object changes with height. At the surface of earth, the value of g is 9.8 m/s2 or 32 ft/sec. The value of acceleration due to gravity decreases due to increase in altitude above the earth surface.

The new absolute determination of acceleration due to gravity has been researched at the National Physical Laboratory. They used a new method as the symmetrical free motion of body moving under the action of gravity. They moved a glass ball and timed its passage across two horizontal planes by flashing of light and it will produced when it will passed between two horizontal slits which are served to define the each plane optically and the ball focusing light from any of the slits, which was illuminated upon the other one and they placed a photomultiplier behind it. They measured the separation of two planes interferometrically. They directly referred the meter by international wavelength definition and the time was measured in terms of atomic unit of time scale. The value of gravity was reduced to  981 181.75 mgal , as 1 mgal=10^-5 m/s2. The systematic errors are considered to be very small; generally this error is due to air resistance. The main contribution of the observed results comes from microseismic disturbances.