Review                                                            Chapter 3                     Cosmic Perspective

MULTIPLE CHOICE.

4)From Kepler's third law, an asteroid with an orbital period of 8 years lies at an average distance from the Sun equal to 4) _______

A)16 astronomical units.

B)2 astronomical units.

C)4 astronomical units.

D)8 astronomical units.

E)It depends on the asteroid's mass.

5)He discovered that Jupiter has moons. 5) _______

A)Ptolemy

B)Aristotle

C)Tycho Brahe

D)Galileo

E)Kepler

7)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? 7) _______

A)Copernicus misjudged the distances between the planets.

B)Copernicus misjudged the speeds at which the planets orbit the Sun.

C)Copernicus used perfect circles for the orbits of the planets.

D)Copernicus placed the planets in the wrong order going outward from the Sun.

E)Copernicus placed the Sun at the center but did not realize that the Moon orbits the earth.

8)All the following statements are true. Which one follows directly from Kepler's third law? 8) _______

A)Venus orbits the Sun at a slower average speed than Mercury.

B)Venus is more massive than Mercury.

C)Venus has a thicker atmosphere than Mercury.

D)Venus is farther from the Sun than Mercury.

12)Kepler's third law, p2 = a3, means that 12) _______

A)planets that are farther from the Sun move at slower average speeds than nearer planets.

B)all orbits with the same semimajor axis have the same period.

C)a planet's period does not depend on the eccentricity of its orbit.

D)the period of a planet does not depend on its mass.

E)All of the above are correct.

13)Kepler's second law, which states that as a planet moves around its orbit it sweeps out equal areas in equal times, means that 13) _______

A)a planet's period does not depend on the eccentricity of its orbit.

B)the period of a planet does not depend on its mass.

C)planets that are farther from the Sun move at slower average speeds than nearer planets.

D)a planet travels faster when it is nearer to the Sun and slower when it is farther from the Sun.

E)planets have circular orbits.