# Astronomy Test 2

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1. The movement of a pool ball, after being struck by a cue, is an example of
Newton's second law of motion.
2. When did Ptolemy live?
3. What is meant by a hypothesis?
an explanation for a phenomenon that makes a prediction
4. When Copernicus first
created his Sun-centered model of the universe, it did not lead to
substantially better predictions of planetary positions than the
Ptolemaic model. Why not?
Copernicus used perfect circles for the orbits of the planets.
5. How does the Space Shuttle take off?
Hot gas shoots out from the rocket and, by conservation of momentum, the shuttle moves in the opposite direction.
6. Which of the following was not observed by Galileo?
stellar parallax
7. What is meant by Occam's Razor?
the idea that scientists should prefer the simpler of two models that agree equally well with observations
8. As long as an object is not gaining or losing mass, a net force on the object will cause a change in
velocity
9. Historians trace the origins of a 24-hour day to
the ancient Egyptians.
10. Ptolemy was important in the history of astronomy because he
developed a model of the solar system that made sufficiently accurate predictions of planetary positions to remain in use for many centuries.
11. If an object's velocity is doubled, its momentum is
doubled.
12. Which of the following is not one of, nor follows directly from, Kepler's laws?
The force of attraction between any two objects decreases with the square of the distance between their centers.
13. How did the Ptolemaic model explain the apparent retrograde motion of the planets?
It held that the planets moved along small circles that moved on larger circles around Earth.
14. Suppose an object is moving in a straight line at 50 mi/hr. According to Newton's first law of motion, the object will
continue to move in the same way until it is acted upon by a force.
15. 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 planet travels faster when it is nearer to the Sun and slower when it is farther from the Sun.
16. He discovered that Jupiter has moons.
Galileo
17. In which of the following cases would you feel weightless?
while falling from a roof
18. During the Dark Ages in Europe, the scientific work of the ancient Greeks was preserved and further developed primarily by scholars in
19. Momentum is defined as
mass times velocity.
20. Which of the following is an example in which you are traveling at constant speed but not at constant velocity?
driving around in a circle at exactly 100 km/hr
21. He was the first to prove that comets lie beyond Earth's atmosphere.
Tycho Brahe
22. He discovered that the orbits of planets are ellipses.
Kepler
23. What is the acceleration of gravity of Earth?
9.8 m/s2 downward
24. By the late 1600s, science and technology in China fell behind that of Europe. Many historians believe that this happened because
a culture of secrecy discouraged broad collaborative efforts.
25. How did Eratosthenes estimate the size of Earth in 240 B.C.?
by comparing the maximum altitude of the Sun in two cities at different latitudes
26. Changing the orbit of a spacecraft by firing thrusters is an example of
Newton's third law of motion.
27. Compared with the standard hour of 60 minutes used today, the hour of ancient Egypt
was longer than 60 minutes in the summer and shorter than 60 minutes in the winter.
28. If your mass is 60 kg on Earth, what would your mass be on the Moon?
60 kg
29. Which of the following statements is not one of Newton's laws of motion?
What goes up must come down.
30. He discovered what we now call Newton's first law of motion.
Galileo
31. What quantities does angular momentum depend upon?
32. You are standing on a scale in an elevator. Suddenly you notice your weight decreases. What do you conclude?
The elevator is accelerating downwards.
33. Newton's second law of motion tells us that the net force applied to an object equals its
mass times acceleration.
34. What would happen if the Space Shuttle were launched with a speed greater than Earth's escape velocity?
It would travel away from Earth into the solar system.
35. A skater can spin faster by pulling her arms closer to her body or spin slower by spreading her arms out from her body. This is due to
conservation of angular momentum.
36. Which ancient culture had the greatest known success in predicting eclipses?
Mayans
37. The controversial book of this famous person, published in 1543 (the year of his death), suggested that Earth and other planets orbit the Sun.
Copernicus
38. Kepler's third law, p2 = a3, means that
All of the above are correct.
39. Which of the following statements about scientific models is true?
A model can be used to explain and predict real phenomena.
40. The fact that the Voyager spacecraft continue to speed out of the solar system, even though its rockets have no fuel, is an example of
Newton's first law of motion.

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 Author: vrk09a ID: 40731 Filename: Astronomy Test 2 Updated: 2010-10-08 21:49:58 Tags: Astron Dowdy Folders: Description: Test 2 Show Answers:

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