Question

At what depth (in terms of the radius of earth) the acceleration due to gravity will be$\frac{2g}{5}$?

Answer 1

$g^{\prime }=g(1-\frac{d}{R})$

$\frac{2g}{5}=g(1-\frac{d}{R})$

$\frac{d}{R}=1-\frac{2}{5};d=\frac{3}{5}R$