A planet has two satellite moons. Moon X has an orbital period of 2.13 days. Moon Y has an orbital period of about 3.53 days. Both moons have nearly circular orbits. Use Kepler's third law to find the distance of each satellite from the planet's center. The planet's mass is 2.0 10^26 kg.

Moon X km?
Moon Y km?

I have posted this earlier but didn't get a respond am sorry to re-post it but I really need help with this!

1 answer

The Kepler's law formula you need to use is:

T²/R³ = 4π²/(GM)

M is the mass of the planet, in kg
G is the universal constant of gravity, which is easily found online.
http://en.wikipedia.org/wiki/Gravitational_constant
T is the period in seconds
Tx = 1.840*10^5 s
Ty = 3.050*10^5 s
R is the orbit radius in meters. Do the calculations of R for planets X and Y, one at a time.