ASTR 151 1st Edition Lecture 5 Outline of Last Lecture II 1 4 Earth s Orbital Motion III 1 5 Motion of the Moon IV 1 6 Measurement of Distance Outline of Current Lecture V Review Chapt 1 Sections 4 6 VI 2 7 Newton s Laws VII 2 8 Newtonian Mechanics Current Lecture II Review a The Moons of Jupiter is the observation that contradicts Galileo s observation that earth is center of galaxy b Kepler is the Renaissance hero who postulated the three laws of planetary motion i Each law is empirically from observation III 2 7 Newton s Laws a Newton s laws explain how objects interact with the world and with each other i Each law explained the motion of objects in general not exclusively planets like Kepler s laws ii Vector Direction and Magnitude b Newton created 3 laws 1 An object stays at rest tends to stay at rest a If it has no change in velocity then it won t move 2 F ma a If force is exerted on an object it s acceleration depends on force implied 3 For every action there exists a reaction a When object exerts force on one object the opposing object exerts force back 4 Gravity a Acceleration of gravity is approximately constant and directed toward the center of the Earth i G 9 8 m s 2 These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute ii Fg mg 75 kg 9 8m s 2 iii F 735N iv N newtons b Gravitational force is weight aimed towards the center of the mass i It is proportional to the product masses IV 2 8 Newtonian Mechanics a G Gravitational constant which roughly equals b Kepler s Laws are consequence of Newton s Laws the first law should be modified i Orbit around the Sun is ellipse with center of the mass of the planet and Sun system at one focus ii Center of Mass weighted relative position of distributed mass sums to zero c Weighing the Sun i The force keeping planets in orbit around the Sun is the gravitational force due to the masses of the planet and Sun d All of the Astronomical Models in chronological order 1 Ptolemic a Earth as the center b Circular orbits i Separate or mini orbits 2 Copernican a Sun as the center b Circular orbits c Confirmed by Galileo s observations 3 Keplers Laws a Orbits around the Sun 4 Newton s laws
View Full Document
Unlocking...