hi Lautrecthanks for the response.found this because i wasnt...

hi Lautrec

thanks for the response.

found this because i wasnt sure if it was a constant?
Reason i say this is because ive seen a world map with different gravity variations so remembered that.
Or could have been something else?

Would depend on the density.

http://www.physicsforums.com/showthread.php?t=203955

Janus
"If you assume a constant density for the Earth, you would get a value of 9.786 m/s, a little under that at the surface. (9.793 m/s)

However, the Earth isn't a constant density and the crust is less dense than the interior.

So, using an value of 2.7g/cm for the density of the Earth's crust, you get 9.797 m/s or slightly more than that at the surface.

So, initially, as you begin to move down towards the center of the Earth, the g force will go increase, but as you continue down, it will begin to eventually decrease unitl it reaches zero at the center. (mainly because as you move closer to the center, the decreasing percentage of the Earth's mass contibuting to the force becomes a larger factor than your decreasing distance from the center.) "