AST101PPT(exam2)

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Unformatted text preview: Welcome back to Astronomy 101 Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. The questions on the first mid-term... • A. took me totally by surprise. I wasn’t expecting them. • B. • C. were kind of what I was expecting came as no surprise. I’d seen them before in class, in the Lecture Tutorials, on the homework and on the past exam papers. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Greek Astronomy Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Modern science traces it’s roots to the ancient Greeks • They developed a tradition of trying to understand nature without using supernatural explanations • They continually debated and challenged each others work Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • They constructed conceptual models of the Universe • These models aimed to predict nature • They used mathematics to give precision to their ideas Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. If you look at the night sky this fall... Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • There are five planets visible with the naked eye • Mercury,Venus, Mars, Jupiter, Saturn • Mercury and Venus are always seen near the Sun • Mars, Jupiter and Saturn can be seen near to or away from the Sun Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Planets orbit the Sun in the ecliptic plane • Planets appear to lie on the celestial sphere • They appear in the constellations of the zodiac • Planets rise in the East and set, in the West Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Celestial Sphere Model The Earth is stationary and the stars are carried on a sphere that rotates about this axis once each day The ecliptic is the Sun’s apparent path around the celestial sphere Stars all appear to lie on in fixed positions the celestial sphere The celestial equator is the projection of the Earth’s equator into space Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Suppose you observe Jupiter at the same time (e.g. midnight) for a few months • Because Jupiter orbits the Sun, its position relative to the background stars will change • It appears to drift west to east through the constellations of the zodiac • But sometimes it moves the other way! Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Altitude W to E Prograde East E to W Retrograde W to E Prograde West Azimuth Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Retrograde Motion • Ancient astronomers could “explain” the motion of the stars, the Sun and the Moon • They imagined that the celestial sphere was real and that it rotated around the Earth once each day • But they could not explain apparent retrograde motion Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. What causes apparent retrograde motion? • We know that all the planets (including the Earth) revolve around the Sun • The outer planets move more slowly than the inner planets Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Think about the Earth and Jupiter • As the Earth passes and overtakes Jupiter in it’s orbit, it appears to go backwards • The same thing happens with the other planets Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Jupiter Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Where would you look to see a planet rise when it is undergoing apparent retrograde motion? • A. • B. on the eastern horizon on the western horizon Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Lecture Tutorial • Observing Retrograde Motion • • Pages 97-98 10 mins Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. A planet moving in retrograde motion. Over the course of one night, with respect to the background stars, it will appear to... • A. move from east to west • B. move from west to east • C. not move very much, as planets move with the stars • D. move randomly, as planets move differently to the stars Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. A planet moving in retrograde motion. Over the course of several nights, how will the planet move relative to the background stars? • A. move from east to west • B. move from west to east • C. not move at all, as planets move with the stars • D. move randomly, as planets move differently to the stars Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. A planet moving in normal (prograde) motion. Over the course of several nights, how will the planet move relative to the background stars? • A. move from east to west • B. move from west to east • C. not move at all, as planets move with the stars • D. move randomly, as planets move differently to the stars Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Mars rises tonight at the exact same moment as a particular star. If Mars is in retrograde motion, then tomorrow night Mars will... • A. • B. • C. rise earlier than this star rise at the same time as this star rise later than this star Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Mars rises tonight at the exact same moment as a particular star. If Mars is in prograde motion, then tomorrow night Mars will... • A. • B. • C. rise earlier than this star rise at the same time as this star rise later than this star Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. How did the Greeks explain apparent retrograde motion? Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Welcome back to Astronomy 101 Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Celestial Sphere Model • Simple model, but does not explain retrograde motion • Two choices: • Abandon for a different simple model • Modify to explain retrograde motion Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Claudius Ptolemaeus Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Epicycles • Each planet is assumed to move on a small circle • This small circle moves around a larger circle Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Why didn’t the ancient Greeks believe in a Sun-centered model? Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Aristarchus Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Stellar Parallax Distant Stars January July Nearby Star July January Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Parallax Angle Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • The parallax angle is half the angular distance that the star appears to move over 6 months • A star with a parallax angle of 1/3600 of a degree (one arc second) is said to be at a distance of one parsec Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. What is the distance to a star (in parsecs) that has a parallax angle of 0.1 arcseconds? • A. • B. • C. • D. 0.01 parsecs 0.1 parsecs 1 parsec 10 parsecs Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Star A is 10 parsecs away and Star B is 50 parsecs away. Which star has the greater parallax angle? • A. • B. Star A Star B Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. 35 arcseconds January Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. 35 arcseconds July Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Parallax and Distance p39-41 • • Work with a partner • Discuss the concepts with one another • Come to a consensus answer you both agree on Read the instructions and questions carefully Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Star A is 10 parsecs away and Star B is 50 parsecs away. What is the parallax angle for Star A? • A. • B. • C. • D. 1/10 arcseconds 1/5 arcseconds 1/2 arcseconds 50 arcseconds Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Star A is 10 parsecs away and Star B is 50 parsecs away. What is the maximum separation between the endpoints for Star B? • A. • B. • C. • D. 1/50 arcseconds 1/25 arcseconds 1 arcseconds 50 arcseconds Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. To measure a star’s parallax angle correctly, you should observe a star’s location against background stars • A. on one night • C. on two nights on two nights separated by one year • D. on many nights • B. separated by 6 months over the course of a year Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. You observe two stars over the course of a year (or more) and find that: Star A has a parallax angle of 1 arcsecond Star B has a parallax angle of 1/2 arcseconds How do the distances to the stars compare? • A. Star A is twice as far away as Star B • B. Star A is the same distance away as Star B • C. Star A is half as far away as Star B Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • • 1 parsec = 2 x 10 AU • 1 parsec = 3.26 light years • Nearest star = 4.2 light years • Betelgeuse = 640 light years 1 parsec = 3 x 1016 m 5 Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. 35 arcseconds January Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. 35 arcseconds July Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • The Greeks could not observe parallax! • Either: • The stars are so far away that parallax is not detectible with the naked eye • The Earth is not moving Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. So what happened? Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Nicholas Copernicus Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Copernicus assumed that the orbits of the planets were perfect circles with the Sun at the center • The Earth rotated and thus the stars, Sun and planets appeared to move around the Earth • Mercury and Venus were closer to the Sun and so always appeared near the Sun • As the Earth passed the outer planets they would appear to undergo retrograde motion Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Welcome back to Astronomy 101 Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Galileo Galilei Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Galileo was the first person to make systematic observations using a telescope • He saw moons orbiting Jupiter Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Galileo’s observations of moons orbiting another world showed that Earth is not special • The Copernican model explains why Mercury and Venus are seen near the Sun • But neither of these observations concretely disprove the celestial sphere model Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. (D) Venus does not appear gibbous in Ptolemy’s model Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Galileo saw phases of Venus Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Galileo’s observations cemented the Copernican Revolution Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Tycho Brahe Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Brahe’s observations did not quite match either Copernicus or Ptolemy’s predictions • The discrepancy in the predicted location of Mars was 8 arc minutes Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Johannes Kepler Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Kepler’s First Law Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • The orbit of each planet is an ellipse with the Sun at one focus Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Which of these objects has the smallest eccentricity? (A) (C) (B) (D) Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Which of these objects has the largest eccentricity? (A) (C) (B) (D) Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Kepler’s Second Law Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • As a planet moves in it’s orbit it sweeps out equal areas in equal times 2 1 3 4 Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. The orbit of a comet around the Sun is shown below. If the comet takes 1 year to move from point 1 to point 2 and 1 year to move from point to 3 to point 4, then the green area must be ______ the red area. (A) larger than (B) equal to (C) smaller than Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. The orbit of a comet around the Sun is shown below. If the comet takes 2 years to move from point 1 to point 2 and 1 year to move from point to 3 to point 4, then the green area must be ______ the red area. (A) larger than (B) equal to (C) smaller than Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. The orbit of a comet around the Sun is shown below. If the comet takes 1 year to move from point 1 to point 2 and 2 years to move from point to 3 to point 4, then the green area must be ______ the red area. (A) larger than (B) equal to (C) smaller than Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Kepler’s Second Law p21-24 • • Work with a partner • Discuss the concepts with one another • Come to a consensus answer you both agree on Read the instructions and questions carefully Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. The orbit of a comet around the Sun is shown below. At which point would the comet’s speed be the largest? (B) (A) (C) (D) Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. The orbit of a comet around the Sun is shown below. At which point would the comet’s speed be the smallest? (B) (A) (C) (D) Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. During how many portions of the planet’s orbit will the planet be speeding up the entire time? (A) During only one of the portions shown (B) During two of the portions shown (C) During all three of the portions shown Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. During which of the portions of the planet’s orbit would the planet experience an increase in speed for at least one moment? (A) During only one of the portions shown (B) During two of the portions shown (C) During all three of the portions shown Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. See you next time... Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Welcome back to Astronomy 101 Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Kepler’s Laws Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. The eccentricity of the Earth’s orbit is e = 0.016 Which of the three orbits shown below most closely matches the shape of the Earth’s orbit around the Sun? (A) (B) (C) Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. During which part of the planet’s orbit (A, B or C) is the planet moving with the greatest speed? Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. During how many portions of the planet’s orbit would the planet experience a decrease in speed for at least one moment? (A) Only one portion (C) During three portions (B) During two portions (D) It is never slowing down Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. During how many portions of the planet’s orbit would the planet be speeding up the entire time? (A) Only one portion (C) During three portions (B) During two portions (D) It is never slowing down Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. With these two rules Kepler could calculate the orbits of any planet Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Is there any relationship between the orbits of the different planets? Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • We measure the size of an elliptical orbit by it’s semi-major axis, “a” • The distance from the center (not the focus) across the widest part a a • The time it takes a planet to complete one orbit is called the planet’s period or “P” Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Planet Period (years) Semimajor axis (AU) Mercury 0.24 0.39 Venus 0.62 0.72 Earth 1.00 1.00 Mars 1.9 1.5 Jupiter 12 5.2 Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. As the orbital distance of the planets increases, the orbital period the planets... • A. increases • B. decreases • C. stays the same Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Which of the following graphs best represents the period of a planet vs its average distance from the Sun? (A) (B) (C) (D) Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. If the orbital distance of a planet is doubled, then its orbital period will • A. stay the same • B. double • C. more than double Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Planet (Period)2 (Semimajor axis)3 Mercury 0.0580 0.0580 Venus 0.378 0.378 Earth 1.00 1.00 Mars 3.54 3.54 Jupiter 141 141 Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Kepler noticed that 2 years) (Period of Orbit in = (Semi-major axis in AU)3 p2 = a3 • More distant planets orbit at slower average speeds • Kepler’s laws apply to any orbiting bodies! Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Does Kepler’s third law mention the mass of the star or the planet? • A. yes • B. no Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Kepler’s third law describes... • A. the relationship between how long it takes a planet to orbit a star and the mass of the star • B. the relationship between how long it takes a planet to orbit a star and the mass of the planet • C. the relationship between how long it takes a planet to orbit a star and how far away the planet is from the star Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. If a small weather satellite and the large International Space Station are orbiting Earth at the same altitude above Earth’s surface, which object takes longer to orbit once around Earth? • A. The large space station • B. The small satellite • C. They would take the same amount of time Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Kepler’s Third Law p25-27 • • Work with a partner • Discuss the concepts with one another • Come to a consensus answer you both agree on Read the instructions and questions carefully Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Which of the following best describes how a planet’s mass will affect its orbital period? • A. Planets that have small masses have longer orbital periods than planets with large masses • B. Planets with the same mass will also have the same orbital period • C. Planets that have large masses will have longer orbital periods than planets with small masses • D. A planet’s mass does not affect its orbital period Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Consider a planet orbiting the Sun. If the mass of the planet doubled but the planet stayed at the same orbital distance, then the planet would take • A. twice as long to orbit the Sun • B. the same amount of time to orbit the Sun • C. half as long to orbit the Sun Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Imagine a new planet in our solar system located 3 AU from the Sun. Which of the following best approximates the orbital period of this planet? • A. 1 year • B. 3 years • C. 5 years • D. 9 years Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Imagine a new planet in our solar system with a period of 8 years. Which of the following best approximates the average distance of this planet from the Sun? • A. 1 AU • B. 4 AU • C. 8 AU • D. 10 AU Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Planet Mercury Venus Earth Mars Jupiter p (years) 0.241 0.615 1.00 1.88 11.9 a (AU) 0.387 0.723 1.00 1.52 5.20 • What is the semi-major axis of the Asteroid Camillo which has an orbital period of 1.67 years? (A) 0.84 AU (C) 2.41 AU (B) 13.7 AU (D) 1.41 AU Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Planet Mercury Venus Earth Mars Jupiter p (years) 0.241 0.615 1.00 1.88 11.9 a (AU) 0.387 0.723 1.00 1.52 5.20 • What is the orbital period of the Asteroid Hathor 2340 which has a semi-major axis of 0.84 AU? (A) 0.77 years (C) 1.67 years (B) 19.2 years (D) 50.2 years Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Communications satellites are often placed in orbits 36,000 km from the Earth. These satellites are ‘geosynchronous’ since they remain fixed above the same position on the Earth. These satellites have an orbital period of... • A. 12 hours • B. 1 day • C. 1 month • D. 1 year Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Participation Credit • Answer the question on your index card • Make sure you carefully explain your reasoning • Write your name and SUID on your card and put it in the boxes by the doors at the end of class Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Why does a planet go faster when it gets closer to the star? Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Momentum Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • The momentum of object going in a straight line is given by its mass times its velocity ( m x v ) • The total momentum of isolated objects is conserved • When I throw the medicine ball, the total momentum of me and the medicine ball is conserved Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Initially the medicine ball and I have zero momentum • We must have zero momentum after I throw the ball to the right • So I start moving to the left so the total momentum stays zero Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Objects going around curves have a property called angular momentum • The total amount of angular momentum of isolated objects is conserved • The direction of the angular momentum of isolated objects is conserved Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. What will happen as they pull the weights closer to their body? • A. spin more slowly • B. spin more quickly • C. nothing will happen Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. What will happen as they turn the bike wheel through 180 degrees? • A. keep spinning in the same direction • B. turn around and spin the other way • C. nothing will happen Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Angular momentum = m × v × r • If the angular momentum is constant then when r is bigger v must be smaller • Conservation of angular momentum explains Kepler’s second law... • ... and why the Earth’s north pole always points towards Polaris Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Why doesn’t the planet’s mass affect it’s orbital period in Kepler’s third law? Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. With air in the cylinder, which will hit the ground first? • A. The billiard ball will hit the ground first • B. The feather will hit the ground first • C. Both will hit the ground at the same time Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. With no air in the cylinder, which will hit the ground first? • A. The billiard ball will hit the ground first • B. The feather will hit the ground first • C. Both will hit the ground at the same time Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. To understand this, we need to look at Newton’s laws... Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Welcome back to Astronomy 101 Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Isaac Newton Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. You just saw one of Newton’s laws in action Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. How do things interact? Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Motion Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Speed tells us how far an object will go in a given amount of time • Velocity gives speed and direction Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Acceleration is the “rate of change” of an object’s velocity • If an objects velocity is changing an any way, the object is accelerating Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Acceleration can change... • A. only an objects speed • B. only an objects direction • C. both its direction and its speed at the same time • D. all of the above are true Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. I am spinning the ball around at a constant speed. Is the ball accelerating? • A. yes • B. no Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Forces can cause objects to accelerate • Gravity exerts a force which can cause objects on Earth to accelerate Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Why does a planet speed up when it gets closer to the star? Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Newton’s Laws of Motion Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Newton realized that the force that made objects fall on Earth was the same as the force that held the moon in orbit • Newton realized that the laws of physics apply everywhere Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Newton’s first law • An object moves at constant velocity if there is no net force acting on it • Objects at rest stay at rest • Moving objects need a force to change their velocity Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. An object is moving in a straight line at constant speed. Which of the following numbers of forces could not be acting on the object? • A. zero • B. one • C. two • D. three Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. An object is moving in a circle at constant speed. Which of the following numbers of forces could not be acting on the object? • A. zero • B. one • C. two • D. three Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Newton’s second law • Force = mass × acceleration • The amount of acceleration depends an objects mass and the net force applied Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Newton’s first law tells us what happens to an object when no forces are present • Newton’s second law tells us how objects behave when forces are present Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Newton’s third law • For every force there is an equal and opposite reaction force Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. When a rocket like the space shuttle takes off... • A. it is pushing off against its launch pad. If the pad was not there the rocket would not take off. • B. the rocket is pushing off against the hot gas coming from the exhaust. It would take off without the launch pad. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Newton’s third law is what makes rockets work • The rocket is propelled upwards by a force equal to the force with which the gas is expelled downwards out of the engines Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Newton’s third law is due to the conservation of momentum • When I throw the medicine ball I exert a force on it... • ...so it exerts an equal and opposite for force on me... • ...so I start accelerating away from the ball Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. See you next time... Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Gravity Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Every mass attracts every other mass through the force of gravity • The strength of the force is proportional to the product of the two masses • The strength of the force is inversely proportional to the square of the distance between them Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Force of gravity Mass of first object Mass of second object Mm F =G 2 r Newton’s constant Distance between objects Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • The force of gravity between two objects: • multiply the masses of the two objects • divide by the square of the distance between them • Remember that they both experience the same gravitational force due to Newton’s third law! Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Newton’s law of gravity describes the attractive force F between masses M and m separated by a distance r Mm F =G 2 r What would the force be in terms of F is the mass M was doubled? • A. F/4 • C. 2F • B. F/2 • D. 4F Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Newton’s law of gravity describes the attractive force F between masses M and m separated by a distance r Mm F =G 2 r What would the force be in terms of F is the distance r was doubled? • A. F/4 • C. 2F • B. F/2 • D. 4F Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Which asteroid exerts the stronger gravitational force on Asteroid C? mC = 1 d=3 d=5 mA = 5 (A) Asteroid A (B) Asteroid B mB = 3 (C) The force exerted by A and B is equal Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Which asteroid exerts the stronger gravitational force on Asteroid C? mC = 1 d=3 d=5 mB = 3 (A) Asteroid A (B) Asteroid B mA = 5 (C) The force exerted by A and B is equal Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Which of the following statements is true? • A. The Earth is pulling on me with a stronger gravitational force than I am pulling on the Earth • B. The Earth is pulling on me with the same gravitational force that I am pulling on the Earth • C. I am pulling on the Earth with a stronger gravitational force than the Earth is pulling on me • D. The Earth exerts a gravitational force on me, but I do not exert a gravitational force on the Earth Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Newton’s Second Law is F = ma • You notice acceleration not force! • a = F/m • Earth is more massive than you are, so you accelerate towards Earth much faster than the Earth accelerates towards you Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Participation Credit • Answer the question on your index card • Make sure you carefully explain your reasoning • Write your name and SUID on your card and put it in the boxes by the doors at the end of class Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. In the task you ranked the strength of the gravitational force on exerted on the asteroid on the left side of the pair. Suppose I asked you to rank the strength of the gravitational force on exerted on the asteroid on the right side of the pair. Would your answer change? • A. Yes • B. No Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. In the task you ranked the strength of the acceleration on exerted on the asteroid on the left side of the pair. Suppose I asked you to rank the strength of the acceleration on exerted on the asteroid on the right side of the pair. Would your answer change? • A. Yes • B. No Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Look at just pair A. Which asteroid experiences the largest acceleration? • A. • B. • C. The one on the left (m = 5) The one on the right (m = 3) They both experience the same acceleration Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Look at just pair A and B. What is the correct ranking for the acceleration of the asteroid on the right side of the pair? • A. • B. • C. A > B (A is greater than B) B > A (B is greater than A) A = B (they are the same) Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Combine Newton’s second law with his law of gravity: MEarth m ma = F = G 2 r MEarth a=G 2 r • The acceleration an object on Earth experiences does not depend on its mass! Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Imagine a spacecraft traveling from the Earth to the Moon. (B) is exactly half way between the Earth and the Moon (B) (C) (A) At what point is the Earth’s force of gravity on the spacecraft the greatest? Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Newton’s Law and Gravity p29 - 31 • • Work with a partner • Discuss the concepts with one another • Come to a consensus answer you both agree on Read the instructions and questions carefully Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. At what point is the Moon’s force of gravity on the spacecraft the greatest? (B) (C) (A) Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. At what point is the Moon’s force of gravity on the spacecraft the greatest? (B) (C) (A) Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Is the net (total) force on the spacecraft at position B zero? (B) (C) (A) (A) yes (B) no Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. In what direction would the net force be pointing if the spaceship is moving towards the Moon at position B? (B) (C) (A) (A) towards the Earth (B) towards the Moon Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Imagine that you throw a ball directly upward. Which of the following statements best describes how Newton’s Second Law accounts for the motion of the ball when it reaches its maximum height? • A. The ball has a velocity that is zero and an acceleration that is zero • B. The ball has a net force that is downward and an acceleration that is downward • C. The ball has a net force that is downward and a velocity that is downward • D. The ball has a net force that is downward and an acceleration of zero Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Mass and Weight Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. • Mass is the amount of matter in your body • Your weight is the force measured by a scale when you stand on it • Weight depends on your mass and all of the forces acting on you (including gravity) Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Your weight on Earth is simply the gravitational force exerted on you by the Earth. Would you weight be more, less or the same on the Moon? • A. more • B. same • C. less Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. A person is stool on a scale in an elevator. When the elevator is stopped, he weighs 180 lbs Stopped Accelerating up Accelerating down When the elevator is accelerating up, will his mass be (A) more, (B) less or (C) the same Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. A person is stool on a scale in an elevator. When the elevator is stopped, he weighs 180 lbs Stopped Accelerating up Accelerating down When the elevator is accelerating up, will his weight be (A) more, (B) less or (C) the same Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. A person is stool on a scale in an elevator. When the elevator is stopped, he weighs 180 lbs Stopped Accelerating up Accelerating down When the elevator is accelerating down, will his weight be (A) more, (B) less or (C) the same Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. This astronaut’s spacesuit has malfunctioned and she is slowly drifting away from the shuttle. Which of Newton’s laws could help her survive? (A) Newton’s first law (B) Newton’s second law (C) Newton’s third law Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). Distribution or reproduction of this material outside blackboard.syr.edy is prohibited. Mid-term 2 is on Thursday. Good Luck! Copyright 2011 Duncan Brown. Copyright images used under "fair use" (17 United Stated Code, Section 107). 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