Q:

Suppose the entire Earth is lying on the ground of a much much muuuuuch larger planet and that planet has the same gravity as Earth has. Now I want to lift the Earth from this planet's surface by using a lever and a pivot (Archimedes). If I intend to use my own weight (70kg) to push down my end of the lever, how long would that lever needs to be if the Earth's center is 6400 km away from the pivot?

- Anonymous

- Anonymous

A:

Great question. After figuring out levers Archimedes posed the same question and stated "Give me a place to stand on and I will move the Earth". At the bottom is a figure reproduced from an engraving in *Mechanics Magazine* published in London in 1824 illustrating the problem. The balance of forces for a first class lever requires W_{1} x L_{1} = W_{2} x L_{2} where the W's are the weight of the earth and you respectively and the L's are

the respective distances from the fulcrum. The mass of the earth is about 6 x 10^{24} Kg. I'll let you do the arithmetic.

Lee.

the respective distances from the fulcrum. The mass of the earth is about 6 x 10

Lee.

*(published on 04/14/2011)*