1 .		What is true about a planet when its orbit is at an aphelion? [Hint]
2 .		The force of gravity between two objects obeys which of the following relationships? [Hint]
3 .		Kepler's second law of planetary motion states that a planet in orbit around the Sun will do which of the following? [Hint]
4 .		Venus is visible from the darkened (night) side of the middle latitudes of Earth under which of the following conditions? [Hint]
5 .		Two otherwise isolated bodies of equal mass will orbit in which of the following configurations as viewed from a fixed distant point? [Hint]
6 .		What was the greatest contribution of Tycho Brahe to astronomy? [Hint]
7 .		In 1859, some astronomers in Europe mistakenly thought that they had discovered a new planet orbiting very close to the Sun with a semi-major axis of 0.143 astronomical units. What would have been the period of this planet's orbit if it had really existed? [Hint]
8 .		Which two of the planets in our solar system are the only ones with orbital eccentricity values larger than 0.1? [Hint]
9 .		Light from the Sun takes about how much time to travel to Earth? [Hint]
10 .		If our Sun were twice as massive as it is now, but the solar system were otherwise identically populated and arranged, how much time would it take for Earth to orbit the Sun? [Hint]
11 .		Was it possible for the geocentric system of Ptolemy to explain the observed retrograde motion of the planets? [Hint]
12 .		Which of the following is not true about the solar system model of Copernicus? [Hint]
13 .		A full moon must always rise at approximately what time of the day or night? [Hint]
14 .		A total lunar eclipse occurs whenever the Moon enters Earth's umbra at which point in its orbit? [Hint]
15 .		Why is a synodic month (the time needed to complete one cycle of lunar phases) longer than a sidereal month (the time taken by the Moon to complete one orbit around Earth) and not shorter? [Hint]
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