Question

Io, a satellite of Jupiter, has an orbital period of 1.77 days and an orbital radius of `4.22 X 10^5` km. From these data, how would you determine the mass of Jupiter?

Answer 1

Use Kepler's 3rd law.

Explanation:

It states that the orbital period, T is related to the distance, r as:

`T^2 = (G.M)/(4pi)r^3` where G is the universal gravitational constant (a very small number for reasons physicists still find hard to explain.)

Rearranging for M should give Jupiter's mass.