- #1
FlyingSpartan
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Homework Statement
If a planet has a diameter of 6*103km and, one of it's satellites is in a circular orbit of radius 9.0*103km with a time period of 8.0 hours.
What is the density of the planet?
Homework Equations
ρ=m/v - density v=4/3 *∏*r2
GMm/r2 = mw2r
The Attempt at a Solution
Firstly convert the Km into M,
Diameter of planet = 6*106 → 3*103
Radius of Satellite = 9.3*106
Time period = 28800s
Where G = 6.7*10-11
Therefore I used
GMm/r2 = mw2rAnd subbing in the values;(6.7*10-11)Mm/(9.3*106+3*106)=m.288002(9.3*106+3*106)So I canceled out the little m and rearranged the equation for M,Giving M an answer as 1.87*1033
I then subbed it into the equation for Density,1.87*1033/4/3*∏(3*106) which gives me an answer of 4.96*1019,
However the given answer is 4.6*103, Any guidance would be appreciated ;D.