The height at which the acceleration due to gravity becomes `g/9`. (Where g = acceleration due to gravity) in terms of R. Where R is the radius of earth

Explanation

`g=(GM)/R^2` and g'=(GM)/(R+h)^2 therefore g'//g=^1//9=GM/((R+h)^2)xxR^2/(GM)=R^2/((R+h)^2)
thereforeR^2=(R+h)^2 therefore3R=R+h=2R`