g - THE ACCELERATION OF GRAVITY CAN BE USED TO FIND

THE EARTH'S DENSITY BECAUSE

g = GM / R2 WHERE

G IS THE CONSTANT OF GRAVITATION,

M IS THE MASS OF THE EARTH, AND

R IS THE RADIUS OF THE EARTH

BECAUSE THE EARTH IS A SPHERE, ITS MASS IS

M= (4/3) R 3

WHERE IS THE AVERAGE DENSITY,

WHICH WORKS OUT TO BE 5.5 GM/CM3

THIS IS ALMOST TWICE THE 2.8-3 GM/CM3

FOR SURFACE ROCKS, DUE TO DENSE IRON CORE