Question

variation of 'g' with depth

Answer 1

Variation of 'g' due to depth. Let us consider the earth to be spherical mass of 'M' and radius 'R'. A body of mass 'm' is placed initially on the surface and finally taken x distance deep into the earth. This expression shows that acceleration due to gravitydecreases as we go deep into the earth.

Answer 2

g=GM/R^2

G is gravitational constant.

M is mass of earth.

R is radius of earth.

So, as radius of earth increases, gravity decreases. It is the reason that gravity decreases as we move up to the surface of earth.

Answer to the question is this that as we move down the surface of earth, gravity increases.

At centre of earth, mass comes to zero and gravity is maximum. So, weight at earth's center is zero.