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  A heavier object would reach the ground faster than a lighter one dropped at the same time from the same height
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  Aristotle theorized that the sun, the moon and the planets all revolved around Earth on a set of celestial spheres.
 Whereas Copernicus proposed that the planets of the solar system revolved around the sun, not Earth.
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  The conculsion of Gallileo's experiments were that freely falling objects experience uniform acceration regardless of mass, as long as extraneous forces, such as air resistance and friction can be minimized.
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  "each thing, as far as in its power, always remains in the same state; and that constently when it is once moved, it always continues to move."
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  The second law sates that "all movement is, of itself, along straight lines". This is also Newton's first law
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  He explained in his three laws why the orbits of the planets are ellipes rather than circles
 He ended up explaining much more in his Principia
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  quantum mechanics and relativity reduce Newton's laws for larger bodies or for bodies moving more slowly