On top of a mountain, or at sea level? What would be the difference?

See my reply to your post in the Engineering forum. As long as the mountaintop and the seashore are on the same planet, your weight will not change.

To be TECHNICAL, however, the strength of gravity is inversely proportional to the distance from the center of the planet. So the strength of gravity will actually be slightly less at the top of the mountain than it is at the seashore.

The nominal value for the strength of gravity on Earth is 9.8 meters per second squared.

[This message was edited by Strider0 on 06-26-02 at 11:41 PM.]

Mr. Chimborazo, mentioned in one of the answers to another of your questions, has the highest peak when measured from the center of the earth. Its elevation is 6310 meters, and its peak's distance from the center of the earth is 6,384,404 meters. The difference between the two is 6,378,094 meters (at sea level).

The formula for your weight places these distances squared in the denominator. The ratio of the distances from the center of the earth squared at the top of Mt. Chimborazo and at sea level is:

6,384,404² : 6,378,094²

which is approximately equal to 1.002. Therefore, if you weigh 100 pounds atop the mountain, you will weigh 100.2 pounds at sea level. Not a heck of a lot of difference, on my scales!

Check out this illustration of how the strength of gravity varies at different places on Earth:

NASA's Grace mission