Question

Which variables are involved in understanding Kepler's third law of motion?
Responses

period of revolution, period of rotation
period of revolution, period of rotation - no response given

eccentricity of orbit, rotational velocity
eccentricity of orbit, rotational velocity - no response given

rotational velocity, distance to sun
rotational velocity, distance to sun - no response given

orbital velocity, distance to sun

Answer 1

Kepler's third law relates the orbital period and the size of the orbit: specifically the period of revolution (P) and the semi‑major axis (a), i.e. the average distance to the Sun. Mathematically: P^2 ∝ a^3 (or, in SI units for bodies orbiting the Sun, P^2 = a^3 when P is in years and a in astronomical units). Rotation period, eccentricity, or rotational/orbital velocity are not the primary variables in the law itself.