Give me a lever long enough and a
fulcrum on which to place it, and I
shall move the world.
-Archimedes
How long would that lever have to be?
That is to say, how long a lever would be needed on Earth, to lift a sphere with the mass of Earth if a human of average size were to sit on the other side of the lever?
Best Answer
The mass of Earth is $6\times10^{24}kg$. If Archimedes can lift 60 kg, he would need a lever with an arm ratio of $10^{23}:1$. So if the short arm is one meter long, the lever length will be $10^{23}$ meters plus one. Also, note that he would have to push the lever for $10^{20}$ meters to shift the Earth just by one millimeter.