AY 101-002 TEST #1 Spring 2009 Answer each of the following on a computer-gradeable answer sheet. Be sure to fill in your name and CWID number (and blacken their circles as well. Note the color of this test and turn in your answer sheet to the matching pile. 1. We experience seasons because a) our distance from the Sun changes. B) OF THE ANGLE BETWEEN THE EARTH'S ORBIT AND ITS EQUATOR. c) the Moon influences the sunlight we receive at various times of year. d) the transparency of our atmosphere changes with our orbital location. 2. The Moon's phases happen because of a) the Earth's shadow falling on different parts of the Moon. B) THE MOON'S ORBIT LETTING US SEE IT AT DIFFERENT ANGLES TO SUNLIGHT. c) the synchronized orbital motion and rotation of the Moon. d) the differences in the surface of the Moon's two hemispheres. 3. Scientists have learned that "Occam's Razor" is often a good guide as to which ideas they should investigate first. This principle says a) Facts should be "shaved away" in search of the underlying pattern. b) New facts demand new explanations. c) The simplest possible explanation must be right. D) THE SIMPLEST EXPLANATION WHICH ACCOUNTS FOR THE DATA IS USUALLY RIGHT. 4. Which of these is not simply a reflection of the Earth's motion? A) MONTHLY MOVEMENT OF THE MOON AROUND OUR SKY. b) Sunrise and sunset. c) Changes in which stars we can see at midnight throughout the year. d) The changing seasons. 5. One of the first clues to the shape of the Earth came from A) ITS SHADOW DURING LUNAR ECLIPSES. b) Newton's discovery that gravity acts in all directions. c) careful surveying of distances between known points. d) the fact that stars rise and set like the Sun. 6. We would see more frequent solar eclipses if a) the Earth and Moon were closer to the Sun. B) THE MOON'S ORBIT WERE EXACTLY ALIGNED WITH THE EARTH'S ORBIT. c) the Moon's orbit took longer than a month. d) the Moon's orbit took it over the Earth's poles. 7. When they happen as close together as possible, a solar eclipse and a lunar eclipse are separated by about a) twelve hours. c) one month. B) TWO WEEKS. d) six months. 8. While we see a lunar eclipse, an observer standing on the Moon would see a) nothing unusual. c) a full Earth. B) A SOLAR ECLIPSE. d) nightfall. 9. Kepler and Newton showed that orbits of objects around the Sun (for example) are A) ELLIPTICAL OR HYPERBOLIC. c) spirals slowly working nward. b) circular or parabolic. d) multiple nested circles. 10. Early skywatchers distinguished Mercury, Venus, Mars, Jupiter, and Saturn a) because of their great brightness. b) because of their large visual size. c) because, unlike stars, we do not see them year-round. D) BECAUSE OF THEIR UNUSUAL (AND ERRATIC) MOVEMENTS. 11. Among Galileo's discoveries, the one most directly distinguishing between Copernicus' Sun-centered scheme and the old Earth-centered one was a) moons of Jupiter. c) sunspots. B) THE PHASES OF VENUS. d) lunar craters and mountains. 12. Building on the measurements by Tycho, Kepler found that planetary orbits are a) circles. b) ellipses centered on the Sun. C) ELLIPSES WITH THE SUN AT ONE FOCUS. d) hyperbolic curves. 13. Newton found that the gravitational force between two objects a) depends only on their masses. B) DEPENDS ON THEIR MASSES AND SEPARATION. c) depends on their chemical composition. d) changes with time. 14. As shown in Kepler's second law, an object in an elongated orbit a) maintains a constant speed throughout. B) MOVES FASTEST WHEN NEAREST THE SUN. c) moves fastest when farthest from the Sun. d) requires a constant supply of energy to maintain this path. 15. The Earth has 80 times the mass of the Moon. If we set the gravitational force with which the Earth pulls the Moon equal to 1, the force with which the Moon pulls the Earth is a) 80 c) 1/80 B) 1 d) zero. 16. One strong point in favor of Copernicus' view of the solar system, even before there was definitive evidence, was a) its more accurate predictions of planetary positions. B) ITS DRAMATIC SIMPLICITY IN ACCOUNTING FOR RETROGRADE MOTION OF PLANETS. c) his adoption of noncircular motions. d) its explanation of the parallax shifts seen in distant stars. 17. According to Newton's laws of motion, if we see something moving at constant velocity, a) a constant force is propelling it. b) it must be freely falling in a gravitational field. C) NO (UNBALANCED) FORCE IS ACTING ON THE OBJECT. d) its acceleration must be at right angles to its motion. 18. Among the planets orbiting the Sun, the more distant ones a) move at the same speed as the closer ones. b) move faster than the closer ones. C) MOVE SLOWER THAN THE CLOSER ONES. d) are not affected by the Sun's gravity. 19. The point of the Apollo 15 lunar-surface video was that a) in the weaker gravity of the Moon, everything falls more slowly than here. B) WHERE THERE IS NO AIR RESISTANCE, EVERYTHING FALLS AT THE SAME SPEED. c) the laws of motion depend on the local environment. d) where there is no gravity, motions cease. 20. Which of these is not a quantity which is conserved in a closed system? a) mass+energy. c) momentum. B) VOLUME. d) angular momentum. 21. Various kinds of electromagnetic radiation - visible, ultraviolet, X-rays, and so on - differ in all these except a) frequency. c) wavelength. b) energy. D) VELOCITY. 22. If we observe an emission spectrum from a gas cloud, we know that A) ATOMS IN THE CLOUD ARE LOSING ENERGY. b) atoms in the cloud are gaining energy. c) that the cloud has some hot background light source. d) the cloud must contain hydrogen. 23. The wavelength where an opaque object emits its strongest radiation is related to its a) chemical composition. c) rotation. b) size. D) TEMPERATURE. 24. The underlying cause of tides is a) water under the Moon being more strongly attracted to it. b) the different strength of gravity acting on solids and liquids. C) THE WAY THE STRENGTH OF GRAVITY FALLS OFF WITH DISTANCE. d) the Earth's rotation imparting a centrifugal acceleration to water. 25. A police officer measuring speeds by using a radar gun is employing a) atmospheric scattering. C) THE DOPPLER SHIFT. b) absorption-line spectra. d) Wien's law. 26. A mirage occurs because of atmospheric a) reflection. c) dispersion. B) REFRACTION. d) absorption. 27. The cause of the red color of the setting sun is related to A) THE BLUE COLOR OF THE SKY. c) the temperature of the atmosphere. b) the Doppler shift. d) the behavior of light in water droplets. 28. A rainbow involves all these processes _except_ a) refraction. c) dispersion. b) reflection. D) ABSORPTION. 29. We would expect to find the coolest stars by looking in the A) INFRARED. c) ultraviolet. b) visible. d) X-ray. 30. As a result of our orbital motion, during the year we see changes in a) which stars are visible during the night. b) the Sun’s north/south location. c) the Sun’s location against the background stars. D) ALL THE ABOVE. 31. An object in orbit 22,300 miles above the Earth’s equator is in geosynchronous orbit, appearing to hang motionless over the rotating Earth. If the Earth rotated twice as fast, this orbital location would be A) CLOSER. b) at the same distance. c) farther away. d) nonexistent. 32. In principle, every part of the sky can be seen at some time from a) the north pole. B) THE EQUATOR. c) the south pole. d) every point on Earth. 33. Tidal forces (such as those that the Moon produces on Earth) a) pile up material under the disturbing object. B) PILE UP MATERIAL TOWARD AND OPPOSITE THE DISTURBING OBJECT. c) affect only certain kinds of matter. d) happen only because of the rotation of the target object (such as Earth). 34. Eratosthenes of Alexandria estimated the size of the Earth, based on A) SHADOWS AT MIDSUMMER. b) sailors’ logs. c) the shadow of the Earth. d) weather patterns at different latitudes. 35. A planet undergoes retrograde motion when it a) changes the direction of its orbit around the Sun. B) APPEARS TO CHANGE ITS NORMAL WEST-TO-EAST MOTION AS SEEN FROM EARTH. c) changes the orientation of its elliptical orbit. d) spins in a direction opposite its orbit. 36. We see the first-quarter moon highest in the sky at about a) noon. B) SUNSET. c) midnight. d) sunrise. 37. Spectra can show emission and absorption lines because a) of the Doppler shift. b) radiation escapes though different-sized spaces between atoms. C) ELECTRONS WITHIN ATOMS CAN TAKE ONLY CERTAIN PRECISE LEVELS OF ENERGY. d) different kinds of atoms are made of different particles. 38. The coolest stars would look a) blue. b) white. c) yellow. D) RED. 39. Which if these kinds of radiation carries the most energy? A) GAMMA RAYS. b) X-rays. c) visible light. d) microwaves. 40.The radius of the Earth is about 8000 miles. Compared to the strength of gravity at the surface, the strength of gravity 16,000 miles from the Earths center is a) the same. b) half as great. C) ¼ AS GREAT. d) 1/8 as great. Assessment questions (not graded): 41. The picture best explaining what we know about our Moon and its origin involves a) the early Earth spinning so fast that it split. B) A GIANT IMPACT ON THE EARTH. c) it forming elsewhere in the solar system. d) Earth and Moon forming together. 42. A remarkable result of the exploration of Mars has been a) detection of primitive life forms growing at the surface. B) SIGNS OF FLOWING WATER IN THE PAST. c) active volcanoes. d) continental drift. 43. The Sun’s energy is derived from a) gravitational contraction of its core. B) FUSION OF HYDROGEN TO HELIUM IN ITS CORE. c) fission of helium to hydrogen in the core. d) the heat of its formation. 44. The main reason for ever-larger telescopes has been a) increased magnification. B) COLLECTING MORE LIGHT FROM FAINT OBJECTS. c) a wider field of view. d) sampling more of the electromagnetic spectrum. 45. The interiors of some planet’s moons are hot for long times, when a) they are rich in radioactive elements. B) TIDES FROM ADJACENT MOONS ALTER THEIR ORBITS. c) their atmospheres drive strong greenhouse effects. d) they rotate fast enough for friction between crust and core heats them.