- #1
NasuSama
- 326
- 3
Homework Statement
Spherical Planet X (mass MX = 7.81x10^24 kg, radius RX = 2.09x10^6 m) travels in a circular orbit of radius ro = 4.39x10^11 m around the star Gort. Its period of orbit is Τ = 390 Earth days.
b) Planet Q is also in circular orbit around the star Gort, at radius 24.76x10^11 m. Find the period of orbit of this planet.
Homework Equations
T²/r² = 4π²/(GM)
The Attempt at a Solution
I found the mass of the Gort to be 4.41 * 10^(31), using the same form I indicated under "equations". Then...
T = √((4.39 * 10^(11) + 24.76 * 10^(11)) * 4π²/(6.67 * 10^(-11) * 4.41 * 10^(31)))
≈ 5.765 * 10^8 seconds
Since 1 day = 24 * 3600 seconds, we have...
5.765 * 10^8 seconds * days / (24 * 3600) seconds → 6673 days, and the answer is marked incorrectly.
I don't get why this happens. I reported this to my professor, and he said that he got the correct answer that is different from the answer I have.