Question

Find the height at which g is reduced to g/2.

Answer 1

Let g/2 = k.
mg = GmM/R^2 => g = GM/R^2.
g/k = 2.
So , g/k = 2 = H^2/R^2 , H = 1.414*R = 9049.6 Km.
Where R is the radius of earth and H is the height at which g becomes g/2.