At what height from the surface of earth will the value of g be reduced by `36%` from the value on the surface? Take radius of earth `R = 6400 km`.

Explanation

`g'= 64% " of "g= (64)/(100)g`
`g' = g(R^2)/((R+h)^2)= (64)/(100)g`
`(R )/(R+h)= (8)/(10)`
`h=(R )/(4)=1600 km`.