lecture9_08 - Tutorial Help Sessions Times and Locations...

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Tutorial Help Sessions Thurs. Oct. 9th, 3-4pm, MP 134 Tues. Oct. 14th, 4-5pm, MP 102 NOTE THE LOCATIONS IN MCLENNAN LABS! Times and Locations
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Term Test Material Everything in Topic 1 of Course Outline, unless otherwise indicated. Test will be 18 multiple-choice questions and 6 simple short-answer questions. Exam room assignments announced at the next lecture. Test on Wed. 15 th Oct. 11-12 (duration 45 minutes).
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The Importance of Newton’s Laws 1. Kepler’s laws can be derived from them (with calculus) . 2. They explain tides and precession. 3. Their use predicted the existence of the planet Neptune. Uranus' orbit perturbed ==> Adams (UK) and Le Verrier (FR) predicted position of perturber (c. 1845), but “couldn't get telescope time”. Galle (Berlin) did get time, discovered Neptune in 1846 after request from Le Verrier. 8th mag., 2.3” dia. [P.289 of text; p.314 of 4 th Ed.] LECTURE 9
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The Importance of Newton’s Laws (cont'd). 4. They provide a way to measure things quantitatively and predict the motion of things. They were the first “laws” that could be shown to hold for both the heavens and the Earth. They offer a unifying view of the universe. 5. Newton’s work confirmed the belief of the ancient Greeks that nature is explainable.
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Beyond Newton: How Science Progresses Beyond Newton: How Science Progresses 1. We defined mass as the measure of the inertia of an object. But in Newton’s law of gravity, however, mass determines the strength of gravitational attraction . The same quantity measures two seemingly different physical properties. 2. Experiments show that the measures of inertia and gravitational attraction are identical to one part in a trillion. This is not a coincidence. i.e. grav. force exactly proportional to mass to limit of measurement. 3. Einstein, in his General Theory of Relativity, showed mathematically that the two types of masses are indeed equivalent. ==> The Principle of Equivalence.
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Illustrating the Principle of Equivalence The Masses are Equal in Each Case
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Measuring the Speed of Light Kepler though light acted instantaneously. Galileo attempted to measure speed of light using lantern signals to and from assistant, but speed was clearly too fast for human reactions (unlike sound). Ole Roemer (Denmark, c. 1675) timed when he saw eclipses of Jupiter's moon Io (orbital period = 42 ½ hours. These were expected to happen at the same time of every orbit, but when the Earth was closer the eclipses were observed sooner, and vice-versa.
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Romer's method of measuring the speed of light Not to Scale EJ(A) = EJ(B) + 2 AU J
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This note was uploaded on 04/22/2009 for the course AST 210 taught by Professor Prof.stefanmochnacki during the Fall '08 term at University of Toronto- Toronto.

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lecture9_08 - Tutorial Help Sessions Times and Locations...

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