Astronomy 1001

1. Which is an unchanging measurement of the amount of matter an object is made of? a. mass b. weight c. both mass and weight; they are the same thing d. neither mass nor weight measures this 2. Which is the measurement of the force that gravity exerts on an object? a. mass b. weight c. both mass and weight; they are the same thing d. neither mass nor weight measures this 3. Which measurement would be different for you on the Moon? a. mass b. weight c. both mass and weight; they are the same thing d. neither mass nor weight measures this

1. a. mass 2. b. weight 3. b. weight

1. What happens if a spinning ice-skater brings her arms in closer to her body? a. Her inertia prevents her from doing this. b. She will spin faster. c. Her rate of spin will not change. d. She will spin slower. 2. Where in an elliptical orbit will a planet have the fastest orbital speed? a. at the points halfway between the points closest and farthest from the Sun b. at the point farthest from the Sun c. at the point closest to the Sun d. actually, orbital speed does not change 3. The changes in the previous two questions are examples of which of the following? a. universal gravitation b. Newton's laws of motion c. conservation of energy d. conservation of angular momentum

1. b. She will spin faster. & 2. c. at the point closest to the Sun & 3. d. conservation of angular momentum

Explain how each of Galileo's telescopic discoveries contradicted the Ptolemaic theory. 1. Surface features on the Moon: a. showed that a planet orbited the Sun b. showed that a heavenly body could be imperfect c. showed that stars were not fixed in the celestial sphere d. showed that the orbits of planets are elliptical e. showed that a heavenly body could have satellites f. does not support or contradict the Ptolemaic theory 2. Stars that are too faint to be seen with the naked eye: a. showed that a planet orbited the Sun b. showed that a heavenly body could be imperfect c. showed that stars were not fixed in the celestial sphere d. showed that the orbits of planets are elliptical e. showed that a heavenly body could have satellites f. does not support or contradict the Ptolemaic theory 3. The moons of Jupiter: a. showed that a planet orbited the Sun b. showed that a heavenly body could be imperfect c. showed that stars were not fixed in the celestial sphere d. showed that the orbits of planets are elliptical e. showed that a heavenly body could have satellites f. does not support or contradict the Ptolemaic theory 4. Sunspots: a. showed that a planet orbited the Sun b. showed that a heavenly body could be imperfect c. showed that stars were not fixed in the celestial sphere d. showed that the orbits of planets are elliptical e. showed that a heavenly body could have satellites f. does not support or contradict the Ptolemaic theory 5. The phases of Venus: a. showed that a planet orbited the Sun b. showed that a heavenly body could be imperfect c. showed that stars were not fixed in the celestial sphere d. showed that the orbits of planets are elliptical e. showed that a heavenly body could have satellites f. does not support or contradict the Ptolemaic theory

1. b. showed that a heavenly body could be imperfect 2. f. does not support or contradict the Ptolemaic theory 3. e. showed that a heavenly body could have satellites 4. b. showed that a heavenly body could be imperfect 5. a. showed that a planet orbited the Sun

How did the magnitude system originate in a classification of stars by apparent brightness? Astronomers measure the brightness of stars using the magnitude scale, attributed in its original form to the Greek astronomer Hipparchus (about 190-120 BC). Ancient astronomers divided the stars into _______ classes: the brightest were called __________ magnitude and the faintest were called _________ magnitude. Modern astronomers can measure magnitude to high precision and have extended the scale to larger numbers for even fainter stars, and to zero and ________ numbers for the brightest stars. The magnitude scale is confusing because it is a(n) __________ scale, meaning that bright objects have smaller magnitudes than fainter objects.

1. six 2. first 3. sixth 4. negative 5. inverse

the evolution of the laws of motion and gravitation Aristotle Kepler Galileo Newton Einstein

Aristotle Assertions: - Objects natural state is to remain at rest - Heavier objects fall faster Proof: None Kepler Assertions: Planets follow elliptical orbits Proof: Precise fit of observations to his simple model. Galileo Assertions: - Objects in motion tend to stay in motion unless acted upon by an external force. - Objects fall at the same rate regardless of mass. Proof: Experiments at Tower of Pisa Newton Assertions: - Universal Law of Gravitation - Laws of physics same on earth and in "Heavens" Proof: Mathematical explanation of natural phenomena Einstein Assertions: - Newton's Laws required correction for speeds approaching the speed of light - Newton's law of universal gravitation needs correction for strong gravitational fields. Results: Special and general theories of relativity Proof: Deflection of light and gravitational lensing

What is a Penumbra? a. Total Shadow b. Partial Shadow What is a Umbra? a. Total Shadow b. Partial Shadow

Penumbra b. Partial Shadow Umbra a. Total Shadow

What is a solar eclipse? a. When the new moon blocks Earth's view of the sun b. When the moon passes through earths shadow and occurs only during full moons What is a lunar eclipse? a. When the new moon blocks Earth's view of the sun b. When the moon passes through earths shadow and occurs only during full moons

Solar When the new moon blocks earths view of the sun Lunar When the moon passes through earths shadow and occurs only during full moons

At which position in the diagram does the planet have the greatest kinetic energy? a. 1 b. 2 c. 3 d. 4 e. The angular momentum is the same at all four points.

a. 1 Kinetic energy refers to motion. It is fasted when it is closest to the sun

The Milky way is one of about ? a. 1-2 trillion galaxies b. 1-2 billion galaxies c. 2 hundred galaxies d. 2 hundred thousand galaxies

a. 1-2 trillion galaxies

How many hours is a solar day? a. 24 b. 24.5 c. 23.5 d. 25 How many hours are in a Sidereal day? a. 23.56 b. 23.25 c.24.56 c. 24.25

a. 24 & a. 23.56

How do stars appear to move looking north? a. Counter-clockwise b. Clockwise c. up-down d. down-up

a. Counter-clockwise

When Tycho observed the new star of 1572, he could detect no parallax. Why did that undermine belief in the Ptolemaic system? In the perfect heavens idea of Aristotle? a. It indicated that the new star was far enough away to be part of the celestial sphere, which was perfect and changeless in both the Ptolemaic model and the perfect heavens of Aristotle. b. Tycho did detect parallax, which convinced him that Earth moved and caused him to believe in the Copernican system. c. It indicated that the new star was not a sphere, which contradicted the perfect geometrical forms required by the Ptolemaic model and the perfect heavens of Aristotle. d. It indicated that the new star did not have a circular epicycle required by the Ptolemaic model and the perfect heavens of Aristotle.

a. It indicated that the new star was far enough away to be part of the celestial sphere, which was perfect and changeless in both the Ptolemaic model and the perfect heavens of Aristotle.

The terrestrial planets in our solar system are? a. Mercury, Venus, Earth , and Mars b. Pluto and Eris c. Earth and Mars d. Io, Europa, Ganymede, and Callisto c. Jupiter, Saturn, Uranus, and Neptune

a. Mercury, Venus, Earth, and Mars

Why did Newton conclude that gravity has to be mutual and universal? a. Newton's third law stated that for every action there is an equal and opposite reaction, so he concluded gravity must be mutual. He reasoned that the Sun, the planets, and all their moons must also attract each other by mutual gravitation, so he concluded that gravity must be universal. b. Newton directly observed that all objects appear to be affected by gravity. Thus he concluded that gravity must be mutual and universal. c. Newton observed that an iron ball and a wooden ball dropped from the top of the Leaning Tower of Pisa would fall together and hit the ground at the same time. Thus he concluded that gravity must be mutual and universal.Newton believed in the Aristotelian universe which asserted that the heavens must be perfect. Therefore, d. Newton concluded that any interaction between heavenly bodies be mutual and universal.

a. Newton's third law stated that for every action there is an equal and opposite reaction, so he concluded gravity must be mutual. He reasoned that the Sun, the planets, and all their moons must also attract each other by mutual gravitation, so he concluded that gravity must be universal.

Why do solar eclipses happen only at new moon? a. Since the shadow of the Moon extends directly away from the Sun, a solar eclipse can occur only when the Moon is between the Earth and the Sun. b. Since the shadow of the Earth extends directly away from the Sun, a solar eclipse can occur only when the Earth is between the Moon and the Sun. c. A solar eclipse can occur only when the Sun is between the Earth and the Moon. d. Solar eclipses can and do occur during other phases of the lunar cycle. Why not every new moon? a. Solar eclipses do occur every new moon at some location on Earth. b. Solar eclipses don't occur every new moon because of variations in the Moon's orbital distance from Earth. c. Solar eclipses don't occur every new moon because of the Moon's orbital tilt. d. Solar eclipses don't occur every new moon because of variations in the intensity of light from the Sun.

a. Since the shadow of the Moon extends directly away from the Sun, a solar eclipse can occur only when the Moon is between the Earth and the Sun. and c. Solar eclipses don't occur on every new moon because of the Moon's orbital tilt.

What is the difference between the moons a sidereal orbit period and synodic orbital period? a. The moons sidereal period is the time it takes the moon to go 360 degree around the earth (27.3 days), and a synodic orbital period is the time from new moon to new moon (29.5 days) b. The moons sidereal period is the time it takes the moon to go 360 degree around the sun (27.3 days), and a synodic orbital period is the moon takes to go around the earth (29.5 days) c. Sidereal period orbit the the time it takes the earth to go around the sun, and the synodic period is the time it take the moon to go around the earth d. None of the above

a. The moons sidereal period is the time it takes the moon to go 360 degree around the earth (27.3 days), and a synodic orbital period is the time from new moon to new moon (29.5 days)

The earth rotates in which direction? a. West to East b. East to West c. North to South d. South to North

a. West to East (Once a day) or Counter-Clockwise

What is the celestial sphere? a. an imaginary sphere centered at Earth. b. the earths north and south poles c. the core of the earth d. the surface of the earth

a. an imaginary sphere centered at Earth.

How do star appear to move looking east? a. away from the horizontal angle b. towards you at the horizontal angle

a. away from the horizontal angle

What do we call the stars near the north celestial pole constantly above the horizon? a. circumpolar b. zenith c. the equator stars d. the horizontal stars

a. circumpolar

According to the Universal law of gravitation, the force due to gravity is a. directly proportional to the square of the distance between two objects b. inversely proportional to the square of the distance between objects c. directly proportional to the distance between objects d. not dependent on the distance between object

a. directly proportional to the square of the distance between two objects

What is the sun mainly made of? a. hydrogen and helium b. hydrogen and oxygen c. carbon and nitrogen e. nearly equal portions of all elements

a. hydrogen and helium Hydrogen 72% Helium 28%

The great contribution of Tycho Brahe was to a. observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion b. discover that planets orbit the sun in an elliptical orbit with varying speed

a. observe planetary positions with sufficient accuracy so that Kepler could later use the date to discover the laws of planetary motion

Which of the following descriptions is a definition of an astronomical unit (AU)? a. the average distance between Earth and the sun b. the distance between the sun and Proxima Centauri c. the distance that light travels in one year one ten-millionth of d. the distance between the equator and the North Pole e. the distance between the king's nose and the tip of his middle finger

a. the average distance between Earth and the sun

Which photo shows what we call a first quarter moon? a. 1 b. 2 c. 3 d. 4

b. 2 1. Crescent moon 2. Quarter moon 3. Gibbous Moon 4. Full moon

How many degrees is the earth tilted? a. 15.5 b. 23.5 c. 22.5 d. 25.5

b. 23.5

What does the word visual mean in apparent visual magnitude? a. It means that the magnitude includes light from the infrared to the ultraviolet range of the electromagnetic spectrum. b. It means that the magnitude includes only light that is visible to the human eye. c. It means that the magnitude includes all wavelengths of light. d. It means that the magnitude includes only light that is visible to machines and the human eye.

b. It means that the magnitude includes only light that is visible to the human eye.

How does Kepler's first law of planetary motion overthrow one of the basic beliefs of classical astronomy? a. Kepler's first law says that the Sun is at one focus of the elliptical orbit, rather than at the center. b. Kepler's first law says that the orbits of the planets are ellipses, rather than perfect circles or series of epicycles. c. Kepler's first law says that the surfaces of planets are slightly elliptical, rather than perfect spheres. d. Kepler's first law says that the planets speed up and slow down during their orbits, rather than remain in uniform motion How about Kepler's second law? a. Kepler's second law says that the Sun is at one focus of the elliptical orbit, rather than at the center. b. Kepler's second law says that the orbits of the planets are ellipses, rather than perfect circles or series of epicycles. c. Kepler's second law says that the surfaces of planets are slightly elliptical, rather than perfect spheres. d. Kepler's second law says that the planets speed up and slow down during their orbits, rather than remain in uniform motion.

b. Kepler's first law says that the orbits of the planets are ellipses, rather than perfect circles or series of epicycles. & d. Kepler's second law says that the planets speed up and slow down during their orbits, rather than remain in uniform motion.

Could a solar-powered spacecraft generate any electricity while passing through the following? Earth's umbral shadow? a. Yes, only a portion of the sun's disk is obscured in this shadow so the solar cells will receive direct sunlight. b. No, this shadow prevents the solar cells from receiving direct sunlight. Earth's penumbral shadow? a. Yes, only a portion of the sun's disk is obscured in this shadow so the solar cells will receive direct sunlight. b. No, this shadow prevents the solar cells from receiving direct sunlight.

b. No, this shadow prevents the solar cells from receiving direct sunlight. and a. Yes, only a portion of the sun's disk is obscured in this shadow so the solar cells will receive direct sunlight.

What, if anything, is wrong with the planetary system orbit shown? a. The shape of the orbit is not an ellipse, as Kepler's first law requires. b. The sun is not at one focus, as Kepler's first law requires c. The orbital path violates Kepler's third law d. There is nothing wrong with this orbit: it is fine as shown.

b. The sun is not at one focus, as Kepler's law requires Has to be OFF center at one focus

What is the difference between the Solar System, the Galaxy, and the Universe? (Select all that apply.) a. The Solar System contains approximately 100 billion stars, of which the sun is one, as well as large clouds of gas and dust. The Galaxy contains thousands of similar Solar Systems. b. The universe contains all physical matter and energy. Its basic constituents are the clusters of galaxies. c. The Solar System is much larger than the Galaxy but much, much smaller than the universe. d. The universe contains all physical matter and energy except for that within galaxies and Solar Systems. e. The Solar System contains the sun and objects that orbit it, including the eight planets, comets, and asteroids, and the Galaxy contains approximately 100 billion stars, of which the sun is one, as well as large clouds of gas and dust.

b. The universe contains all physical matter and energy. Its basic constituents are the clusters of galaxies. and e. The Solar System contains the sun and objects that orbit it, including the eight planets, comets, and asteroids, and the Galaxy contains approximately 100 billion stars, of which the sun is one, as well as large clouds of gas and dust.

Which statement below most accurately describes modern constellations? a. They are 13 well defined sky regions along the ecliptic. b. They are 88 well defined regions on the celestial sphere. c. They are 88 groups of stars with members of each constellation physically close together in space. d. They are 88 connect-the-dot mythological sky figures. e. They are 13 connect-the-dot mythological sky figures along the ecliptic.

b. They are 88 well defined regions on the celestial sphere.

Why are light-years more convenient than miles, kilometers, or astronomical units (AU) for measuring the distances to stars and galaxies? (Select all that apply.) a. because only light-years can provide an accurate measurement of how far light travels across the universe b. because in viewing a distant galaxy, the distance in light-years to the galaxy tells us how far back in time we are viewing the galaxy c. because light-years are the units astronomers have been using since the beginning of modern astronomy and are used only to be consistent with historical convention d. because distances between objects in the universe are very large compared to the distances between objects on Earth and in our solar system, and measuring distances between objects in the universe in miles, kilometers, or astronomical units would require using very large numbers

b. because in viewing a distant galaxy, the distance in light-years to the galaxy tells us how far back in time we are viewing the galaxy and d. because distances between objects in the universe are very large compared to the distances between objects on Earth and in our solar system, and measuring distances between objects in the universe in miles, kilometers, or astronomical units would require using very large numbers

Suppose an object is moving in a straight line at 70km/hr. According to Newton's first law of motion, the object will a. continue to move in the same way forever, no matter what happens b. continue to move in the same way until it is acted upon by a force c. eventually slow down and come to a stop d. continue to move in a straight line forever if it is in space, but fall to the ground if it is on earth

b. continue to move in the same way until it is acted upon by a force

The Great Contribution of Nicholas Copernicus was to? a. discover the law of gravity b. create a detailed model of our solar system with the sun rather than Earth at the center

b. create a detailed model of our solar system with the sun rather than Earth at the center

The term observable universe refers to? a. the portion of the universe that can be seen by the naked eye b. the portion of the universe that we can see in a principle, given the current age of the universe c. that portion of the universe that we have so far photographed through telescopes d. the portion the of universe that is not hidden from view by, for example, being below the horizon

b. the portion of the universe that we can see in a principle, given the current age of the universe

Which of the figures shown here is that of a single galaxy?

c

What is the age of the universe? a. 20.7 billion years b. 5.2 billion years c. 13.8 billion years d. 4.5 billion years

c. 13.8 billion years

At which position in the diagram does the planet have the greatest gravitational potential energy? a. 1 b. 2 c. 3 d. 4 e. The angular momentum is the same at all four points.

c. 3 the further it is from the sun the greater the gravitational potential energy.

How many arcseconds are in one degree? a. 60 b. 360 c. 3,600 d. 100 e. 1,000

c. 3,600

Approximately how many astronomical units (AU) are there in one light year (ly)? a. 1,000,000 b. 1,000,000,000 c. 63,000 d. 5,280 e. 12

c. 63,000

Which of the following is not a general difference between a planet and a star? a. Planets are dimmer than stars. b. Planets are smaller than stars c. All planets are made of rock and all stars are made of gas d. Planets orbit stars, while stars orbit the center of the galaxy.

c. All planets are made of rock and all stars are made of gas example : Jupiter and Saturn are planets made of gas

Why did Copernicus have to keep small epicycles in his models? a. Actually, Copernicus did not use epicycles. b. Unlike the Ptolemaic system, all the planets were treated the same. c. His model did not predict planetary positions as well as the Ptolemaic system. d. It was the only way to explain retrograde motion. Which planet has the longest duration of retrograde motion as viewed from Earth? a. Mars b. Jupiter c. Saturn d. Uranus e. Neptune Which planet has the shortest duration of retrograde motion as viewed from Earth? a. Mars b. Jupiter c. Saturn d. Uranus e. Neptune

c. His model did not predict planetary positions as well as the Ptolemaic system. & e. Neptune & a. Mars

North is up in this figure. Can we tell whether the daylight and darkness line at the right is the sunset line or the sunrise line? a. No, we can't tell. b. It is the sunset line because Earth rotates clockwise when viewed from above Earth's North Pole. c. It is the sunset line because Earth rotates counterclockwise when viewed from above Earth's North Pole. d. It is the sunrise line because Earth rotates clockwise when viewed from above Earth's North Pole. e. It is the sunrise line because Earth rotates counterclockwise when viewed from above Earth's North Pole.

c. It is the sunset line because Earth rotates counterclockwise when viewed from above Earth's the North Pole. ** Earth rotates counter-clockwise

What does the word apparent mean in apparent visual magnitude? a. It means that the magnitude describes how bright the star actually is on its surface. b. It means that the magnitude describes how bright the star actually is, observing from anywhere in the Universe. c. It means that the magnitude describes how bright the star appears to us, observing from Earth. d. It means that the magnitude describes the average apparent brightness of a star, over its entire lifetime, as observed from Earth.

c. It means that the magnitude describes how bright the star appears to us, observing from Earth.

Our solar system consists of? a. The sun, planets, and nothing else b. The sun and several nearby stars, as well as the planets and other objects that orbit these stars c. the sun and all the objects that orbit it d. a few hundred billion stars, bound together by gravity

c. The sun and all the objects that orbit it

Notice in this figure that the magnitude scale is "awkward" in that the smaller, or more negative, magnitude number corresponds to a brighter star. Why does this scale have this "awkward" direction? a. Measurements of brightness had large errors when the scale was introduced. b. All systems based on brightness must be set up this way. c. The system was originally set up as a set of classes with first class as the brightest. d. The system is designed to make astronomy more difficult. e. The negative direction is due to the fact that we see stars as they were, not as they are.

c. The system was originally set up as a set of classes with first class as the brightest.

How far must a spacecraft go to be "beyond Earth's gravity"? a. farther away than the Moon b. outside of the solar system c. actually, a spacecraft can never be completely out of Earth's gravity d. farther away than the Sun What is the reason for the answer to the last question? a. All objects exert at least a small amount of gravity on all other objects, no matter how far away they are from each other. b. Since Earth orbits the Sun and not vice-versa, we know that Earth's gravity does not act beyond the Sun. c. Outside the solar system, no gravity from any planet will be felt. d. The Moon is the only object orbiting Earth, so we know that Earth's gravity does not act beyond the Moon.

c. actually, a spacecraft can never be completely out of Earth's gravity & a. All objects exert at least a small amount of gravity on all other objects, no matter how far away they are from each other.

Earth is made of mostly atom metals and rocks. Where did this material come from? a. It was produced in the Big Bang b. It was created by chemical reactions in the interstellar space c. It was produced by nuclear fusion in stars d. It was made by our Sun e. It was made by nuclear fission of uranium and other radioactive materials

c. it was produced by nuclear fusion in stars

Where is zenith in your local sky? a. the sky to your right (pointing your finger right) b. the earth below you (pointing your finger down) c. the sky above you (pointing your finger up) d. the sky to your left (pointing your finger left)

c. the sky above you (pointing your finger up)

You are located in St. Louis, MO, United States. Your friend is located in Buenos Aires, Argentina. You see a waning gibbous in your clear night sky. What phase, if any, will your friend see if the night sky in Buenos Aires is also clear? a. full moon b. first quarter c. waning gibbous d. new moon e. the moon cannot be visible from both St. Louis and Buenos Aires on the same night

c. waning gibbous The same side of the earth sees the same face

Which of these ellipses has the greatest eccentricity? a. 1 b. 2 c. 3 d. 4

d. 4 eccentricity refers to the elongation of the ellipse, how far the foci are from each other.

Diagrams like this one are commonly used in discussion of seasons and they can be quite useful. However, this diagram greatly exaggerates: a. the size of the Earth relative to the size of earths orbit around the sun. b. the size of the Sun relative to the size of Earth's orbit around the sun. c. The amount by which Earth's orbit differs from a perfect circle. d. All of the above e. only the first and third choices above

d. All of the above

What did Plato propose about all heavenly motion? a. It is in elliptical paths. b. Only its shadow can be seen on Earth. d. It is incomprehensible from Earth. d. It is in circular paths. Why did Plato propose what he did about heavenly motion and the shape of heavenly objects? a. because of the shape of the sun and the moon b. because he believed the sphere to be the most perfect geometrical form c. because Earth seems to be a disk around us, and the sky appears to be a spherical shell above us d. because of his telescopic observations What effect did Plato's proposal have on future astronomers? a. His idea of a sphere being the most perfect geometric form influenced astronomical theories for literally hundreds of years. b. None, at least outside of his homeland, Greece. c. His idea of elliptical orbits was "rediscovered" by Kepler. d. None at all; being a philosopher and not an astronomer, what he said was ignored.

d. It is in circular paths. and b. because he believed the sphere to be the most perfect geometrical form and a. His idea of a sphere being the most perfect geometric form influenced astronomical theories for literally hundreds of years.

Which statement much be true in order for a rocket to travel from Earth to another planet? a. It must be launched from space, rather than from the ground. b. It must carry a lot of extra fuel c. It must have very large engines d. It must attain escape velocity from Earth

d. It must attain escape velocity from Earth

If you drop a feather and a steel hammer at the same moment, they should hit the ground at the same instant. Why doesn't this work on Earth, and why does it work on the Moon? a. It is a common misconception that the hammer and feather will not hit the ground at the same time. On the Moon as on Earth, both will hit the ground at the same instant. b. On Earth, the mass of the feather is much less than the mass of the hammer, so the hammer accelerates at a much greater rate than the feather. On the Moon, the mass of the feather and hammer are equal, so both accelerate at the same rate. c. On the Moon as on Earth, the hammer and feather will not hit the ground at the same instant. This effect is much more difficult to observe on the Moon because the acceleration due to gravity is so much smaller than it is on Earth. d. On Earth, air resistance slows the feather, which falls at a nearly constant speed, while the hammer accelerates downward, constantly increasing its speed. On the Moon, there is no atmosphere so the motion of the feather is not impeded by air resistance, and both the feather and hammer continue to accelerate as they fall. Will it work on Phobos, a moon of Mars? (Consider that Phobos is a very small, low-density, rocky moon with no atmosphere.) a. Yes b. No

d. On Earth, air resistance slows the feather, which falls at a nearly constant speed, while the hammer accelerates downward, constantly increasing its speed. On the Moon, there is no atmosphere so the motion of the feather is not impeded by air resistance, and both the feather and hammer continue to accelerate as they fall. & a. Yes

Why are solar eclipses separated by one Saros cycle not visible from the same location on earth? a. The Saros cycle is defined as the time required for a solar eclipse to occur at the same location on Earth, and hence, solar eclipses separated by one Saros cycle are visible from the same location on Earth by definition. b. Solar eclipses separated by one Saros cycle are visible from the same location on Earth only for extreme northern latitudes. c. The Saros cycle is 29.53 days long. Thus it takes 100 Saros cycles for the Moon to return to the same relative position with respect to any location on Earth. d. The Saros cycle is 18 years, 11 1/3 days long. The one-third of a day means that the eclipse will occur when Earth has rotated one-third of a day further, and hence, the eclipse will occur one-third of the way around Earth from the original one.

d. The Saros cycle is 18 years, 11 1/3 days long. The one-third of a day means that the eclipse will occur when Earth has rotated one-third of a day further, and hence, the eclipse will occur one-third of the way around Earth from the original one.

How does the Greek-letter designation of a star give you clues both to its location and its brightness? a. The constellation name describes the star's brightness relative to other stars in other constellations and the Greek letter indicates its location in the sky. The brighter stars have constellation names whose first letter is nearer the end of the Roman alphabet. b. The constellation name describes the star's brightness relative to stars in other constellations and the Greek letter indicates its location in the sky. The brighter stars have constellation names whose first letter is nearer the beginning of the Roman alphabet. c. The constellation name describes the star's location in the sky and the Greek letter indicates its brightness relative to the other stars in the constellation. The brighter stars have Greek letters nearer the end of the Greek alphabet. d. The constellation name describes the star's location in the sky and the Greek letter indicates its brightness relative to the other stars in the constellation. The brighter stars have Greek letters nearer the beginning of the Greek alphabet.

d. The constellation name describes the star's location in the sky and the Greek letter indicates its brightness relative to the other stars in the constellation. The brighter stars have Greek letters nearer the beginning of the Greek alphabet.

In Ptolemy's model, how do the epicycles of Mercury and Venus differ from those of Mars, Jupiter, and Saturn? a. The epicycles of Mercury and Venus were perfect circles. The epicycles of Mars, Jupiter, and Saturn were elliptical. b. The epicycles of Mercury and Venus revolved around Earth independently of the Sun. c. The epicycles of Mars, Jupiter, and Saturn were attached to a line joining Earth and the Sun. The epicycles of Mercury and Venus were identical to the epicycles of Mars, Jupiter, and Saturn in Ptolemy's model. d. The epicycles of Mercury and Venus were attached to a line joining Earth and the Sun. The epicycles of Mars, Jupiter, and Saturn revolved around Earth independently of the Sun.

d. The epicycles of Mercury and Venus were attached to a line joining Earth and the Sun. The epicycles of Mars, Jupiter, and Saturn revolved around Earth independently of the Sun.

What is the difference between speed and velocity? a. There is no difference between an object's speed and its velocity.Speed is an object's rate of motion. b. Velocity is the rate of change of an object's speed. c. Velocity is an object's rate of motion. Speed is the rate of change of an object's velocity. d. The velocity of an object indicates both the object's speed (rate of motion) and its direction of motion. e. The speed of an object indicates both the object's velocity (rate of motion) and its direction of motion.

d. The velocity of an object indicates both the object's speed (rate of motion) and its direction of motion.

Longitude is measured east to west from? a. Greenwich b. prime meridian c. north pole d. south pole e. Both a & b are correct

e. Both a & b are correct

At which position in the diagram does the planet have the greatest angular momentum? a. 1 b. 2 c. 3 d. 4 e. The angular momentum is the same at all four points.

e. The angular momentum is the same at all four points. Angular momentum is a conserved quantity, it does not change. The reason it doesn't change leads to the planet moving fast the closer it gets to the sun and slow the further it moves away from the sun to conserve angular momentum.

Which of the following best describes the milky Way galaxy? a. A spiral galaxy with a disk about a billion kilometers in diameter and containing between 100 million and 1 billion stars b. A spiral galaxy with a disk about 100,000 light-years in a diameter and containing about 100,000 stars c. a spherically shaped collection of stars including our solar system about a dozen other solar systems stretching about 4 light-years in diameter d. a spherically shaped collection of about 1 million stars that is about 100 light-years in diameter e. a spiral galaxy with a disk about 100,000 light-years in diameter and containing between 100 billion and 1 trillion stars

e. a spiral galaxy with a disk about 100,000 light years in diameter and containing between 100 billion and 1 trillion stars

Which of the following statements is true? a. Both the Northern and Southern hemispheres receive the same amount of sunlight on the equinoxes. b. Both the northern and southern hemispheres receive the same amount of sunlight on the solstices. c. The northern Hemisphere receives the most direct sunlight on the summer solstice. d. The Southern Hemisphere receives the most direct sunlight on the summer solstice. e. Both A and C are true.

e. both A and C are true

If Earth had no atmosphere, what color would the eclipsed moon appear in the sky? a. coppery-red b. dark blue c. light blue d. mustard-yellow e. dark, essentially invisible

e. dark, essentially invisible