ASTR 151 1st Edition Lecture 5 Outline of Last Lecture II. 1.4 Earth`s Orbital MotionIII. 1.5 Motion of the MoonIV. 1.6 Measurement of DistanceOutline of Current Lecture V. Review Chapt 1, Sections 4 - 6VI. 2.7 Newton`s LawsVII. 2.8 Newtonian MechanicsCurrent LectureII. Reviewa. 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 motioni. Each law is empirically from observationIII. 2.7 Newton`s Lawsa. Newton`s laws explain how objects interact with the world and with each otheri. Each law explained the motion of objects in general, not exclusively planets like Kepler`s lawsii. Vector = Direction and Magnitudeb. Newton created 3 laws1. An object stays at rest tends to stay at resta. If it has no change in velocity then it won`t move2. F=maa. If force is exerted on an object, it`s acceleration depends on force implied3. For every action, there exists a reactiona. When object exerts force on one object, the opposing object exerts force back4. Gravitya. Acceleration of gravity is approximately constant, and directed toward the center of the Earthi. G=9.8 m/s^2These 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^2iii. F=735Niv. N=newtonsb. Gravitational force is weight aimed towards the center of the massi. It is proportional to the product massesIV. 2.8 Newtonian Mechanicsa. “G” = Gravitational constant which roughly equalsb. Kepler`s Laws are consequence of Newton`s Laws – the first law should be modifiedi. Orbit around the Sun is ellipse with center of the mass of the planet and Sun system at one focusii. Center of Mass = weighted relative position of distributed mass sums to zeroc. Weighing the Suni. The force keeping planets in orbit around the Sun is the gravitational force due to the masses of the planet and Sund. All of the Astronomical Models in chronological order;1. Ptolemica. Earth as the centerb. Circular orbitsi. Separate or mini orbits2. Copernicana. Sun as the centerb. Circular orbitsc. Confirmed by Galileo`s observations3. Keplers Lawsa. Orbits around the Sun4. Newton`s
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