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43 Cards in this Set
- Front
- Back
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Kepler 1st Law
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Planets move in elliptical orbits
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Kepler 2nd Law
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Objects orbiting sweep equal areas in equal amounts of time
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Kepler 3rd Law
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Their is an algebraic relationship between a planet's orbital period and it's average distance from the sun
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What were the three major Aristotleian objections that Galileo overcame?
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(1) Earth could not be moving because it would leave objects behind. (2) Non-circular orbits are not perfect and the heavens are. (3) If earth were really orbiting the sun, we should detect stellar paralax
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A scientific theory MUST
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(1) Explain a variety of observations with a few simple principles, (2) Be supported by lots of evidence, (3) Not fail any crucial tests of validity
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Force is
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the means of changing an object's momentum
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Newton's First Law of Motion says
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An object in rest stays at rest, and an object in motion stays in motion and moves in a straight line at a constant speed
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Newton's Second Law of Motion says
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When force is applied, a body's speed or direction or both will change
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Newton's Third Law of Motion says
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For every every force there is an equal and opposite force
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Which of these is not conserved: Momentum, Angular Momentum, Energy?
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All of them are conserved
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What explains why a planet will keep orbiting around the sun?
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Conservation of Angular Momentum. Unless a torque is applied, angular momentum will be conserved
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What does Newton's Universal Law of Gravitation explain?
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It accounts for Kepler's Law and explains the motion of the planets around the sun
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Is starting place relevant for an object in orbit?
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No. The only thing that matters is the speed, distance and direction
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What makes matter move?
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Enagy (energy)
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What is radiative energy? Thermal Energy?
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Photons. The Kinetic Energy of many particles
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What does conservation of mechanical energy say?
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PE+KE= constant. Mechanical energy can be neither created nor destroyed. The total mechanical energy of the universe is completely constate
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Is potential energy absolute?
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No. We can potential energy to be whatever we want it to be and only differences in potential energy are significant. Standard procedure is to set PE=0 when an object is infinitely far away
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How was the earth formed?
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Collapse of a large cloud of matter
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What are forces that act on charges?
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Electric and Magnetic Fields
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How can we describe a photon in terms of E-M?
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It is an electromagnetic disturbance
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How does a charge relate to light and EM radiation?
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Accelerating charges produce oscillating EM fields that emit energy at the speed of light and these oscillating fields are electromagnetic radiation
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What did Planck hypothesize?
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EM radiation (oscillating fields moving at the speed of light) comes in little packets of energy called quanta
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Einstein showed photons to be...
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...literally real
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The chemical properties of different compounds depend on...
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... the number of electrons in the outer shells
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What is the basic principle of quantum physics?
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An electron behaves like a wave but is a particle
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Only certain orbits are allowed...
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.. to an electron. These are called quantum states (?)
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Match these types of radiation in order of their wavelength (from shortest to longest): visible, gamma ray, radio, x-rays, ultraviolet, infrared
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Gamma Rays, X Rays, Ultraviolet, Visible, Infrared, Radio
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Each quantum state is associated with a total energy. What determines the amount of energy and what are the differences?
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Distance from the nucleus. Close to the nucleus, low energy and vice versa
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When an electron moves from one state to another it may gain or lose energy. What explains this?
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It either gains or loses energy to make up the difference of energy in the states
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How can we figure out the magnitude of the energy change?
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By using Planck's constant and the frequency of the radiation emitted or absorbed
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What is a blackbody spectrum?
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Something that emits light at all wavelengths
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EM Radiation=...
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...blackbody radiation
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What variables does the amount of radiation depend on?
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Surface temperature of object, surface area
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What is angular resolution?
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The minimum angular separation that a telescope can distinguish
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What is the limiting factor to angular resolution?
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Interference of light waves within a telescope
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Why are larger telescopes capable of greater resolution?
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Because there is less interference with the light waves within the telescope
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What are the differences between refracting and reflecting telescopes?
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Refracting: Focuses light with lenses. Reflecting: Focuses light with mirrors
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What are the disadvantages of refracting telescopes?
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Chromatic abberation (?), Transmission of light varies with the wavelength of light, Difficult to make a glass with no internal imperfections
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Who invented the reflecting telescope?
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Isaac Newton
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What are the 3 primary uses of telescopes?
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Imaging (pictures of sky), Spectroscopy (breaking light into spectra), Timing (measuring how light output varies with time, ?)
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What is the technique of using multiple satellites to improve the angular resolution?
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Interferometry (easiest to do with radio telescopes)
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What two variables do we use to determine an object's celestial coordinates and what are the earthly analogues?
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Right Ascension, analogous to longitude, and Declination, analogous to latitude (vertical position)
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When is the Sun's declination positive and negative?
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Positive: summer and spring, negative: winter and fall
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