'A body acted on by [two] forces acting jointly...', 1687.
© Science Museum / Science & Society Picture Library
Corollary 1, Axioms, or the Laws of Motion, from the first edition of Newton's 'Principia Mathematica' (1687): 'A body acted on by [two] forces acting jointly describes the diagonal of a parallelogram in the same time in which it would describe the sides if the forces were acting separately.' The discoveries of English physicist and mathematician Isaac Newton (1642-1727) were prolific and hugely influential on science and thought. His work included the three laws of motion, the theory of gravitation, the law of cooling, the binomial theorem and the calculus.