English astronomer Sir Isaac Newton (1643-1727) is most famous for his work on forces, specifically gravity. He calculated three laws describing the motion of forces between objects, known today as Newton's laws.
Sixth Grade Science News: November 2011; "Physics is essentially an intuitive and concrete science. Mathematics is only a means for expressing the laws that govern phenomena." - Albert Einstein; Quote Source: http://en.wikiquote.org/wiki/Albert_Einstein#Albert_Einstein:_A_guide_for_the_perplexed_.281979.29 ; From Lettre à Maurice Solvine, by A. Einstein (Gauthier-Villars: Paris 1956).