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Slide 1 Newton (1642 - 1727) Slide 2 Newton Born 1642 - the year Galileo died Graduated from Cambridge 1665 Because of the plague he returned to Woolsthorpe (1665 - 1667) During these two year he developed: - the binomial theorem - calculus - decomposition of white light into colours - began studying motion (mechanics) - formulated his ideas about gravitation Slide 3 - Returned to Cambridge as a lecturer in 1667 - Noted mathematician Isaac Barrow resigned his chair of mathematics so that Newton could freely follow his studies - Newton’s first publications (optics) were not well received by the British scientific community - Newton studied alchemy, theology, and Biblical prophecy and did not publish again for 20 years. - Described as :jealous, egotistical, complex, and troubled. Absent-minded, confirmed bachelor - Had heated rivalries with Flamsteed and Leibnitz Slide 4 Most important published work : Principia Mathematica - Used rigorous logic and axiomatic style (Euclid) - From a number of basic definitions three laws of motion and the law of universal gravitation were proposed - By deduction Newton showed that the observed motions of objects were consequences of his definitions and laws of motion Slide 5 Newton’s Ideas: - Quantity of matter (mass) - Quantity of motion ( mass X velocity) (momentum) - Inertia - Impressed force - Fundamental quantities mass, time, and length, i.e. dimensions (Required to be measurable independent of the state of mind of the observer) Slide 6 Three Laws of Motion 1. In the absence of a net external force, an object will continue in a state of uniform motion (including rest) in a straight line (Law of Inertia) 2. The time rate of change of motion (momentum) of an object is directly proportional to the magnitude and direction of the impressed force F = ma (Law of Acceleration) 3. For every action there is an equal and opposite reaction (Law of Action and Reaction) Slide 7 Universal Law of Gravitation Every material particle in the universe attracts every other material particle with a force that is proportional to the product of the masses of the two particles and inversely proportional to the square of the distance between their centres. The force of attraction is directed along a line joining their centres. F = G m1m2 r2 Conservation Laws - conservation of mass - conservation of momentum