Planetary Motion – Kepler’s Third Law
Student Page
Purpose
To study applications of Kepler’s Third Law of Planetary Motion.
Before you Begin
If a planet were twice as far away from the Sun as the Earth, predict how long would it
take to orbit the Sun?
A.J.J.A.R. Programs Required
Kepler’s Third Law (all versions)
Questions
Using the first “Kepler’s Third Law” program:
1. If a planet were twice as far away from the Sun as the Earth, how long would it take
to orbit the Sun?
Using the second “Kepler’s Third Law” program:
2. Kepler’s Third Law states that the period of a planet’s orbit squared is equal to the
length of the planet’s semimajor axis cubed. For planets orbiting the Sun
P2=a3
, where P is in years and a is in astronomical units.
Using three examples provided by the A.J.J.A.R. program, calculate the period (in
years) for the orbit given the orbital distance (in A.U.). Record both the orbital
distance and the period you calculate.
Using the third “Kepler’s Third Law” program:
3. Do the same as you did in the previous problem, only now calculate the average
orbital distance (in A.U.) given the period (in years). Do this for three examples and
record the period and the orbital distance you calculate.
Using the fifth “Kepler’s Third Law” program:
