In the simplified version of Kepler's third law,P² = a³,the units of the orbital period P and the semimajor axis of the ellipse a must be,respectively:
A) years and light-years.
B) years and astronomical units.
C) years and meters.
D) seconds and meters.

Question

Quizplus · Accepted Answer

In Kepler's third law, P² = a³. The units of P are usually taken in years since it represents the time taken for one complete orbit. The units of a are usually taken in astronomical units (AU) since it represents the average distance between the center of mass of the two objects (e.g. a planet and a star). Therefore, the answer is B – years (for P) and astronomical units (for a).

In the Simplified Version of Kepler's Third Law,P² = A³,the