Chapter 4

1. Which of the following was a consequence of Tycho's failure to detect parallaxes of stars? it convinced him that the earth was stationary
it convinced him that the stars are very far away
it convinced him that Saturn was the outermost planet
it convinced him that stars are bigger than the solar system
2. Which of the following is one of Kepler's Laws of Planetary Motion planets move on elliptical orbits with the Sun at one focus
gravitational force between two objects decreases as the distance squared
an object in motion remains in motion
inner planets orbit in a different direction than outer ones
3. Suppose a planet has an elliptical orbit. The speed of the planet is 20 kms when it is at its average distance from the sun. Which of the following is most likely to be the planet's speed when it is nearest the sun? 10 kms
15 kms
20 kms
25 kms
4. A hypothetical planet orbits the sun a distance of 3 AU. What is its orbital period? 2.8 years
3.0 years
5.2 years
9.0 years
5. It has been suggested that there are very remote planets in the solar system, with periods of about ten million years. Approximately how far from the Sun would such a planet be? 100 astronomical units
5000 astronomical units
50000 astronomical units
500000 astronomical units
6. In which of the following models of the solar system is it possible for stars to show parallaxes? none of the other answers is correct
Ptolemy's model
Copernicus' model
Tycho's model
7. When does retrograde motion of Jupiter occur in the heliocentric model of the solar system? when the earth passes Jupiter
when the earth and Jupiter are on opposite sides of the sun
when the earth is nearest the sun
when the sun and Jupiter are seen close together in the sky
8. A shift in the direction of an object caused by a change in the position of an observer is called parallax
the Coriolis effect
epicycle motion
9. A planet has a synodic period of 3 years. What is the sidereal (orbital) period of the planet? 23 year
1 year
1.5 years
3 years
10. What was the significance of Galileo's discovery that Venus shows all phases from new to full? it allowed him to find Venus' distance from the sun
it proved to other astronomers that his telescope was working correctly
in the geocentric model, only some phases are possible
it proved that Venus has an atmospher