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AY2 Fall 2014 Midterm
Prof. C. Rockosi
November 4, 2014
Name and Student ID __________________________________
Section Number _______ Section Day/Time_________
Select the best answer for each question. Write your name and student ID on this printed exam. Both your Scantron form
and this printed exam need to be turned in for you to get credit for the exam.
1) Two of the stars closest to the Sun are Alpha Centauri A and B. The distance between the two
stars is 3.45 x 109 km. Their measured angular separation is 29.7 arcseconds. What is their
1)
distance to the Earth in kilometers (you can assume that both are at the same distance from the
Earth)?
A) 1.52 x 1014 km
B) 5.8 x 1014 km
C) 1.8 x 1013 km
D) 2.39 x 1013 km
2) According to Kepler's third law (p2 = a3), how does a planet's mass affect its orbit around the
Sun?
A) More massive planets orbit the Sun at higher average speed.
B) A more massive planet must have a larger semimajor axis.
C) More massive planets must have more circular orbits.
D) A planet's mass has no effect on its orbit around the Sun.
2)
3) By locating the north celestial pole (NCP) in the sky, how can you determine your latitude?
A) The altitude of the NCP is the same as your distance from the North Pole.
B) The azimuth of the NCP is the same as your latitude.
C) The altitude of the NCP is the same as your latitude.
D) The altitude of the NCP is your angular distance from the North Pole.
E) The azimuth of the NCP is the angular distance from the North Pole.
3)
4) Imagine another solar system, with a star of the same mass as the Sun. Suppose there is a planet
in that solar system with a mass of 2MEarth orbiting at a distance of 1 AU from the star. What
4)
(approximately) is the orbital period of this planet?
A) About the same as the earth's orbital period
B) Two times slower than the earth's orbital period
C) Twice as fast as the earth's orbital period
D) Four times slower than the earth's orbital period
5) If our year were twice as long (that is, if Earth took twice as many days to complete each orbit
around the Sun), but Earth's rotation period and axis tilt were unchanged, then
A) stars would take twice as long to rise and set.
B) the four seasons would each be twice as long as they are now.
C) the Earth would not have seasons.
D) the cycle of precession would take 13,000 years instead of 26,000 years.
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5)
6) The Moon is constantly falling toward Earth.
A) True
B) False
6)
7) Which of the following statements about the celestial equator is true at all latitudes?
A) It cuts the dome of your sky exactly in half.
B) It extends from your horizon due north, through your zenith, to your horizon due south.
C) It represents an extension of Earth's equator onto the celestial sphere.
D) It extends from your horizon due east, through your zenith, to your horizon due west.
E) It lies along the band of light we call the Milky Way.
7)
8) Which of the following is not one of, nor follows directly from, Kepler's laws?
A) A planet travels faster when it is nearer to the Sun and slower when it is farther from the
Sun.
B) More distant planets move at slower speeds.
C) The more eccectric a planet's orbit is, the faster its average speed as it orbits the Sun.
D) The orbit of each planet about the Sun is an ellipse with the Sun at one focus.
E) As a planet moves around its orbit, it sweeps out equal areas in equal times.
8)
9) What is the average speed of the Earth in its orbit around the Sun, in kilometers per hour?
A) 100 km/hour
B) 150,000,000 km/hour
C) 110,000 km/hour
D) 110,000,000 km/hour
9)
10) How many arcseconds are in 1°?
A) 3,600
B) 100
C) 10,000
D) 60
E) 360
10)
11) If an object's velocity is doubled, its momentum is
A) dependent on its acceleration.
B) doubled.
C) quadrupled.
D) halved.
E) unchanged.
11)
12) If you drop a rock from a great height, about how fast will it be falling after 5 seconds,
12)
neglecting air resistance? You can approximate the acceleration of gravity on earth as 10 m/s2.
A) It depends on what shape it is.
B) 50 m/s
C) It depends on how heavy it is.
D) 15 m/s
E) 10 m/s
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A
13) What does temperature measure?
A) the average mass of particles in a substance
B) the total number of particles in a substance
C) the total potential energy of particles in a substance
D) the average kinetic energy of particles in a substance
E) the average size of particles in a substance
13)
14) The International Space Station orbits at a distance of 400 km above the surface of the Earth. The
moon orbits the earth at a distance of 384,000 km. A geostationary satellite oribts the earth at a
distance of 42,000 km. Which of these three has to be given the largest velocity in order to
escape from orbit around the earth?
A) The International Space Station
B) The moon
C) The geostationary satellite
D) You can't tell, because you don't know the masses of the three objects
14)
15) What is stellar parallax?
A) It is the change in the set of constellations that we see at different times of year in the
evening sky.
B) It is the daily rise and set of the stars.
C) It describes the fact that stars are actually moving relative to one another, even though to
our eyes the stars appear fixed in the constellations.
D) It is the slight back-and-forth shifting of star positions that occurs as we view the stars
from different positions in Earth's orbit of the Sun.
15)
16) Commercial airplanes fly at altitudes (distance from the surface of the Earth) of 9 km (about
30,000 feet). You see a new 787 Boeing Dreamliner fly overhead and measure its angular size to
be 0.36 degrees. What is its size in meters?
A) 86.2 m
B) 56.7 m
C) 52.5 m
D) 20.8 m
16)
17) How long does it take the Earth to complete one orbit around the Sun?
A) one month
B) one year
C) one week
D) one day
E) The time it takes Earth to orbit the Sun changes significantly from one orbit to the next.
17)
18) Suppose a comet orbits the Sun on a highly eccentric orbit with an average (semimajor axis)
distance of 1 AU. How long does it take to complete each orbit, and how do we know?
A) It depends on the eccentricity of the orbit, as described by Kepler's first law.
B) One year, which we know from Kepler's third law.
C) Each orbit should take about 2 years, because the eccentricity is so large.
D) It depends on the eccentricity of the orbit, as described by Kepler's second law.
18)
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19) How does Earth's varying distance from the Sun affect our seasons?
A) It doesn'tEarth's orbital distance plays no significant role in the seasons.
B) It is responsible for the fact that the seasons are opposite in the Northern and Southern
hemispheres.
C) It causes the seasons to be more extreme than they would be if the Earth's distance from
the Sun were always the same.
D) It makes summer warmer in the Northern Hemisphere than in the Southern Hemisphere.
19)
20) Suppose you lived on the Moon. Which of the following would be true?
A) Your mass would be less than your mass on Earth, but your weight would be the same as
it is on Earth.
B) Both your weight and your mass would be the same as they are on Earth.
C) Your weight would be less than your weight on Earth, but your mass would be the same
as it is on Earth.
D) Both your weight and your mass would be less than they are on Earth.
20)
21) Which of the following best describes why we have seasons on Earth?
A) Earth's elliptical orbit means we are closer to the Sun and therefore receive more intense
sunlight at some times of year than at others.
B) The varying speed of Earth in its orbit around the Sun gives us summer when we are
moving fastest and winter when we are moving slowest.
C) The tilt of Earth's axis causes the northern hemisphere to be closer to the Sun than the
southern hemisphere in summer, and visa versa in winter.
D) The tilt of Earth's axis causes different portions of the Earth to receive more or less direct
sunlight at different times of year.
21)
22) From Kepler's third law, a hypothetical planet that is twice as far from the Sun as Earth should
have a period of
A) 2 Earth years.
B) 1 Earth year.
C) 1/2 Earth year.
D) more than 2 Earth years.
E) It depends on the planet's mass.
22)
23) Which object has the most kinetic energy?
A) a 1-ton truck moving 110 km/hr
B) a 4-ton truck moving 50 km/hr
C) a 3-ton truck moving 70 km/hr
D) a 2-ton truck moving 90 km/hr
E) A, B, C, and D all have the same kinetic energy.
23)
24) The planet Nepture has a mass of 1x1026 kg and a radius of 24,500 km. If you stand on the
surface of Neptune and drop a ball, what is its acceleration?
A) 2.7x108 m/s2
24)
B) 11.1 m/s2
C) 1.1x107 m/s2
D) 9.8 m/s2
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25) Kepler's second law, which states that as a planet moves around its orbit it sweeps out equal
areas in equal times, means that
A) the period of a planet does not depend on its mass.
B) a planet's period does not depend on the eccentricity of its orbit.
C) planets that are farther from the Sun move at slower average speeds than nearer planets.
D) planets have circular orbits.
E) a planet travels faster when it is nearer to the Sun and slower when it is farther from the
Sun.
25)
26) According to the universal law of gravitation, if you double the masses of both attracting objects,
then the gravitational force between them will
A) decrease by a factor of 2.
B) not change at all.
C) increase by a factor of 4.
D) decrease by a factor of 4.
E) increase by a factor of 2.
26)
27) Two planets, A and B, orbit the Sun at a distance of 3 AU. Planet A has an eccentricity of 0.1
Planet B has an eccentricity of 0.7. Which planet is going at the greatest speed when it is closest
to the sun?
A) Both are going at the same speed.
B) There isn't enough information here to determine the answer.
C) Planet B
D) Planet A
27)
28) One light-hour is the distance that light travels in an hour. How far is this, in kilometers? (Recall
that the speed of light is 300,000 km/s.)
A) 1.08 billion km
B) 18 million km
C) 9.46 trillion km
D) 100 million km
E) 300,000 km
28)
29) If it is midnight in New York, it is
A) midday in Rio de Janeiro, Brazil.
B) daytime in Sydney, Australia.
C) midnight in Sydney, Australia.
D) midnight everywhere.
E) midnight in Los Angeles.
29)
30) Two racecars are going around a corner. Both drivers read 180 miles per hour on their
speedometers. The cars are identical and the riders are identical twins, so both cars have the
same mass. Once car, painted blue, is close to the inside edge of the corner. The other car,
painted red, is on the outside edge. Which car has the larger angular momentum?
A) The blue car
B) Can't tell because you need to know the acceleration of the cars.
C) They have the same angular momentum
D) The red car
30)
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31) The planet Jupiter has a moon, Callisto, that orbits Jupiter every 16.69 days at an average
distance of 1.9x109m. What is the mass of Jupiter? You may neglect the mass of Callisto in
31)
comparison to the mass of Jupiter.
A) 1.4x1037 kg
B) 5.4x108 kg
C) 2x1027 kg
D) 1.3x1017 kg
32) The angular diameter the Sun as seem from Earth is 0.53 degrees. The diameter of the moon is
2,240 kilometers. What is the diameter of the sun in kilometers?
A) 2.2 x 105 km
32)
B) 2.7 x 106
C) 1.38 x 106 km
D) 1.38 x 109 km
33) If you are driving at 30 miles per hour and increase your speed to 60 miles per hour, you
quadruple your kinetic energy.
A) True
B) False
33)
34) After the midterm, you drop your AY2 textbook and #2 pencil out your third floor window. You
drop them both at the same time. Which one do you expect to hit the ground first? You can
neglect air resistance for this problem.
A) The pencil
B) Can't tell, it depends on the number of pages ripped out of the textbook.
C) Both hit at the same time
D) The textbook
34)
35) Which of the following represents a case in which you are not accelerating?
A) going from 0 to 60 miles per hour in 10 seconds
B) driving 60 miles per hour around a curve
C) driving in a straight line at 60 miles per hour
D) slamming on the brakes to come to a stop at a stop sign
35)
36) The force of gravity is an inverse square law. This means that, if you double the distance
between two large masses, the gravitational force between them
A) strengthens by a factor of 4.
B) also doubles.
C) weakens by a factor of 2.
D) is unaffected.
E) weakens by a factor of 4.
36)
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37) You are standing on a scale in an elevator. Suddenly you notice your weight decreases. What do
you conclude?
A) The elevator is moving at a constant velocity downwards.
B) The elevator is moving at a constant velocity upwards.
C) The elevator is accelerating downwards.
D) The elevator is accelerating upwards.
E) Your diet is working.
37)
38) From Kepler's third law, an asteroid with an orbital period of 8 years lies at an average distance
from the Sun equal to
A) 8 astronomical units.
B) 4 astronomical units.
C) 16 astronomical units.
D) 2 astronomical units.
E) It depends on the asteroid's mass.
38)
39) When we look at an object that is 1,000 light-years away we see it
A) as it is right now, but it appears 1,000 times dimmer.
B) as it was 1,000 years ago.
C) as it was 1,000 light-years ago.
D) looking just the same as our ancestors would have seen it 1,000 years ago.
39)
40) Planet X takes 6.5 years to orbit the Sun. Planet Q takes 3 years to orbit the Sun. Planet B takes
11 years to obrbit the Sun. Which of the following correctly orders the average distances of
planets X, Q and B from the Sun from smallest to largest?
A) X,Q,B
B) B,Q,X
C) Q,X,B
D) X,B,Q
40)
41) Which object has the more gravitational potential energy?
A) A motorcyle parked on the 2nd floor of the parking garage
B) A Metro bus parked on the 3rd floor of the parking garage
C) A Metro bus parked on the ground floor of the parking garage
D) A bicycle locked in a rack on the 2nd floor of the parking garage
41)
42) In any particular place on Earth, certain constellations are visible in the evening only at certain
times of the year because
A) on any particular night, we can only see stars that are directly opposite (180 degrees away
from) the Sun in the sky.
B) our evening view of space depends on where Earth is located in its orbit around the Sun.
C) some constellations are circumpolar.
D) during some times of year, some constellations drop below the southern horizon.
42)
43) All the following statements are true. Which one explains the reason that there is not a solar
eclipse at every new Moon?
A) The nodes of the Moon's orbit precess with an 18-year period.
B) The Moon is only about 1/4 as large as Earth in diameter.
C) The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane.
D) The Moon goes through a complete cycle of phases about every 29 1/2 days.
43)
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44) If you were standing on Earth's equator, where would you look to see the north celestial pole?
A) toward the ecliptic
B) directly overhead
C) due east
D) on your horizon due north
44)
45) What is an astronomical unit?
A) any basic unit used in astronomy
B) the average speed of Earth around the Sun
C) the average distance from Earth to the Sun
D) the length of time it takes Earth to revolve around the Sun
E) the diameter of Earth's orbit around the Sun
45)
46) Suppose a solar system has a star that is four times more massive than our Sun. If that solar
system has a planet the same size as Earth, orbiting at a distance of 1 AU, what is the orbital
period of the planet?
A) The same as the earth's orbital period
B) Four times longer than the earth's orbital period
C) Half of the earth's orbital period
D) Twice the earth's orbital period
46)
47) According to the universal law of gravitation, if you triple the distance between two objects, then
the gravitational force between them will
A) decrease by a factor of 6.
B) increase by a factor of 3.
C) decrease by a factor of 9.
D) decrease by a factor of 3.
E) increase by a factor of 9.
47)
48) Newton's second law of motion tells us that the net force applied to an object equals its
A) energy times acceleration.
B) mass times acceleration.
C) mass times energy.
D) mass times velocity.
E) momentum times velocity.
48)
49) Suppose an object is moving in a straight line at 50 miles/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) continually slow down but never quite come to a complete stop.
C) continue to move in the same way until it is acted upon by a force.
D) continue to move in a straight line forever if it is in space, but slow and stop otherwise.
E) eventually slow down and come to a stop.
49)
50) If your mass is 60 kg on Earth, what would your mass be on the Moon?
A) 10 lb
B) 60 kg
C) 10 kg
D) 60 lb
E) 50 kg
50)
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Answer Key
Testname: AY2_2014_MIDTERMA
1) D
2) D
3) C
4) A
5) B
6) A
7) C
8) C
9) C
10) A
11) B
12) B
13) D
14) A
15) D
16) B
17) B
18) B
19) A
20) C
21) D
22) D
23) D
24) B
25) E
26) C
27) C
28) A
29) B
30) D
31) C
32) C
33) A
34) C
35) C
36) E
37) C
38) B
39) B
40) C
41) B
42) B
43) C
44) D
45) C
46) C
47) C
48) B
49) C
50) B
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