PHYS 1062 1st EditionExam # 2 Study Guide Chapters: 5, 9-10Chapter 5● Kepler used the precise observational tables of Tycho Brahe to study planetary motion mathematically, found consistent description by abandoning both circular motion and uniform motion● Kepler’s Law of Planetary Motion: 1) the orbit of the planets are ellipses with the sun at one focus, eccentricity: e = c/a, ● 2) a line from a planet to the sun sweeps over equal areas in equal intervals of time● 3) a planet’s orbital period (P) squared is proportional to its average distance from the sun(a) cubed, Py^2 = aAU^3 (Py is period in years and aAU is distance in AU)● Newton refined Kepler’s laws of planetary motion● Before Galileo, the philosophical idea of understanding science was to sit and ponder nature● Aristotle believed that all things were a combination of earth, fire, water, and air. Since light (from the Sun, Moon, and Stars) came from above, air and fire ought to want to rise,and earth and water will want to fall back to the earth, also defined two forces: natural motion and violent motion, and that when forced to stop the motion will stop● Galileo realized that more was required than just pondering nature like experimentation, he experimented and proved that all objects fall at the same rate towards the earth, also proved that this motion isn’t constant rather accelerated called acceleration of gravity● The closer to the earth’s surface, the faster the acceleration of gravity● Acceleration of gravity increases by 9.8m/s● Galileo realized that balls rolling down an inclined plane all accelerated, reasoned that they would slow down rolling up, also reasoned that no plane, flat surface, would cause the ball to roll consistently in same direction and speed● Newton’s Laws of Motion: 1) a body at rest will stay at rest or a body in motion will stay in motion, unless an outside force changes that fact.● 2) A body’s acceleration is inversely proportional to its mass, directly proportional to its mass, directly proportional to the net force, and in the same direction as the net force● 3) For every action, there is an equal and opposite reaction● Law 1) An object either at rest or moving in a straight line with constant velocity will continue until another force acts upon it, until a force acts on a body it will not move and conserve momentum● Conservation of Momentum: momentum is preserved until the body moves● Law 2) Force: F = ma, the acceleration and mass of the object is equal to its amount of force, the stronger the force the stronger the response. Net Force: the total amount of 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.forces combined and expressed as one force, total of the force going one way and a force fighting said force● Law 3) For every action there is an equal opposite reaction, for example: person sits in chair, person exerts force downward and chair exerts force upward (unless its weak, then it breaks)● Gravity: universal force of attraction between all particles of matter● Newton’s Law of Gravitation: the force attraction F between two masses m1 and m2 is inversely proportional to the square of their separation, r.● Field: the region in which a physical agency exerts an influence, measured in terms of theforce experienced by an object in that region● Law of Universal Gravitation: every object in the universe attracts every other object with a force directed along the line of centers for the two objects that is proportional to the product of their masses and inversely proportional to the square of the separation between two objectsFg = G (m1xm2/r^2)Fg is the gravitational forcem1 & m2 ar the masses of the two objectsr is the separation between the objectsG is the universal gravitational constant● Everything in the universe is attracted to everything in the universe, attractive forces are related to the masses of the objects and distance between them, the farther away they are the less force exists between them, the more massive they are the stronger the force will be and farther the range of gravity● Orbital Motion: actual motion of “falling,” moving too slowly to leave orbit but moves fast enough to not miss or hit the object being orbited, does not orbit an object rather bothorbit a common center of mass● Escape velocity: the minimum velocity that a body needs to leave orbit● Angular Momentum: a property of any rotating or revolving system whose value dependson the distribution of mass and velocity about the axis of rotation or revolution, ● Corrections to Kepler’s laws made by Newton: 1) bodies orbit a common center of mass, not “little body orbiting a big body,” 2) equation is mtotal x P^2 = a^3● Stars are held together by their own gravity, but the gravity is actually trying to collapse them into smaller denser bodies, high temperatures create high pressures that try to explode them, if the effects of self gravity and thermal pressure are balanced, the star is stable● Stars begin as a cloud of gas undergoing gravitational collapse and then fusion reactions generate energy which proves an outward thermal pressure, this outward pressure perfectly balances inward force of gravity, the pressure inside of a star is strongest where the strongest gravity is● Gravitational equilibrium: balance of these pressures which stabilizes the star● We study our star, the Sun, because of its connection to climate and life and stuff on Earth● Also, the Sun is connected to the “weather” in Space, source of solar winds which influences the Earth’s magnetic field, also has flares of UV light and X rays which can disrupt satellites● The Sun serves as a model for other astronomical objects because its the only star close enough for us to study its surface and composition● Composition known by identifying the absorption lines in the sun’s spectrum● (notes on plasma and sun’s layers)● 1H + 1H = 2H + positron + neutrino2H + 1H = 3He + energy3He + 3He = 4He + 1H +1H + energy● A solar photon starts in the Core where nuclear fusion takes place, then travels through the Radiation Zone (takes 170000 yrs), and then cycles through the Convection Zone forever● A solar neutrino moves through the sun faster than a photon and can penetrate huge amounts of material without being absorbed● The sun can be