Discuss the variation of g with depth and derive the necessary formula.
OR
Show that the gravitational acceleration due to the earth at a depth d from its surface is `g_d= g[1- frac(d)(R)]`, where R is the radius of the earth and g is the gravitional acceleration at the earth's surface.
OR
Discus the variation of acceleration due to gravity with depth 'd' below the surface of the earth
OR
Derive an expression for acceleration due to gravity at depth 'd' below the surface of earth