The acceleration due to gravity at a point A at certain height from surface of the earth is $\frac{g}{4}$ where 'g' is acceleration due to gravity on the surface of the earth. At a point B which lies vertically at certain height above point A, the acceleration due to gravity is $\frac{g}{9}$. The distance between points A and B is (R - Radius of the earth)}
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Remember:
\[
g_h=g\left(\frac{R}{R+h}\right)^2
\]
At height \(R\), gravity becomes \(\frac{g}{4}\).