1. The problem statement, all variables and given/known data We know that 'g' decreases with height and the derivation for the formula is straight enough, but how is the formula for decrease of 'g' with depth derived? 3. The attempt at a solution If an object is taken to a height 'h' above the surface of the earth and assuming the radius of the earth as 'R', then acceleration due to gravity at a height 'h' is given by the formula gh = GM/(R+h)2 After adding R2 to both denominator and numerator, we get the formula gh = g[R/(R+h)]2 However, the same formula will not work for depth because if (R-h) is substituted for (R+h) in the above formula, then the value of 'gh' will actually increase, which is not the case. I know that the correct formula to be used here is gh = g[(R-h)/R], but how is that derived ? I know this is pretty basic but I am not able to get the hang of it. Would appreciate if somebody can please explain.