Question

How much below the surface of earth acc due for gravity become 1% of its value on the surface of earth ?

Answer 1

$\begin{array}{c}{g}^{{}^{\prime }}=g\left(1-\frac{2d}{Re}\right)\\ \Rightarrow \frac{1}{100}g=g\left(1-\frac{2d}{Re}\right)\\ \Rightarrow \frac{99}{100}=\frac{2d}{Re}\\ \Rightarrow d=\frac{99}{100}\times \frac{Re}{2}\\ \therefore q=\frac{99}{200}Re\end{array}$

Which is the required answer.