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Physics help!?
In the third century B.C., Archimedes said, “Give me a long enough lever and a firm fulcrum and I will lift the earth.” Disregarding the mass of the lever, and assuming the weight of the earth is 5.85 x 10^25 N, Archimedes’ weight is 858 N, and the distance from the earth to the moon is 3.84 x 10^8 m, answer the following:
a. Using the moon as a fixed fulcrum, how long a lever would Archimedes have needed to lift the earth?
1 Answer
- Anonymous4 years ago
The Earth has the stated weight only if it is placed in a gravitational field of 9.8 m/s²; you can't "weigh" it in its own surface gravitational field.
That notwithstanding, A. needs the moment created by his weight on his side of the lever to exceed the moment created by the Earth on the other side of the lever, or
858N * (L - 3.84E8m) = 5.85E25N * 3.84E8m
where L is the length of the lever. This solves to
min L = 2.62E31 m