Remember that the MAss of the earth is all BENEATH
you when you use G(Mm)/r^2 while at the earths surface. So some things change as you go into the earth
ARe parts of the Mm values different as you burrow down into the earth? or are the r values the only things that change?
In other words, as you burrow into the earth isnt an increasing amount of the value of the mass above you the deeper you go ?