# Kepler's laws of planetary motion: Quiz

Question 1: A line joining a planet and the Sun sweeps out equal ________ during equal intervals of time.
AreaPolygonTriangleSphere

Question 2: At the time, Kepler's laws were radical claims; the prevailing belief (particularly in ________-based theories) was that orbits should be based on perfect circles.
Geocentric modelHeliocentrismAlmagestDeferent and epicycle

Question 3: Detailed calculations for the orbit of the planet Mars first indicated to Kepler its elliptical shape, and he inferred that other heavenly bodies, including those farther away from the ________, have elliptical orbits too.
Solar SystemSunStarEarth

Question 4: where (rθ) are heliocentric ________ for the planet, p is the semi-latus rectum, and ε is the eccentricity.
Geography and cartography in medieval IslamExponentiationMathematics in medieval IslamPolar coordinate system

Question 5: The "areal velocity" is proportional to angular momentum, and so for the same reasons, Kepler's second law is also in effect a statement of the conservation of ________.
Rigid bodyAngular momentumForceEnergy

Question 6: Newton's law of universal gravitation describes how masses attract each other through the force of ________.
GravitationEquivalence principleIntroduction to general relativityGeneral relativity

Question 7: The square of the ________ of a planet is directly proportional to the cube of the semi-major axis of its orbit.
InclinationStandard gravitational parameterOrbital periodApsis

Question 8: In the special case where there are only two particles, the motion of the bodies is the exactly soluble ________, of which an approximate example is the motion of a planet around the Sun according to Kepler's laws, as shown below.
Laplace–Runge–Lenz vectorGravitational two-body problemTwo-body problemEuler's three-body problem

Question 9: The ________ of circular motion is proportional to a/P2, and it is provided by the gravitational force, which is proportional to 1/a2.
Centripetal forceCentrifugal force (rotating reference frame)Fictitious forceKinematics

Question 10: Bodies with highly eccentric orbits have been identified, among them the comets and many ________, discovered after Kepler's time.
Ceres (dwarf planet)Kuiper beltAsteroid beltAsteroid