Answer
The mass of Rhea is $2.32\times 10^{21}~kg$.
The average density of Rhea is $1240~kg/m^3$.
Work Step by Step
We can find the mass of Rhea.
$\frac{G~M}{R^2} = 0.265~m/s^2$
$M = \frac{R^2~(0.265~m/s^2)}{G}$
$M = \frac{(7.64\times 10^5~m)^2~(0.265~m/s^2)}{6.67\times 10^{-11}~m^3/kg~s^2}$
$M = 2.32\times 10^{21}~kg$
The mass of Rhea is $2.32\times 10^{21}~kg$.
We can find the volume of Rhea.
$V = \frac{4}{3}~\pi~R^3$
$V = \frac{4}{3}~\pi~(7.64\times 10^5~m)^3$
$V = 1.87\times 10^{18}~m^3$
We can find the average density of Rhea.
$\rho = \frac{Mass}{Volume}$
$\rho = \frac{2.32\times 10^{21}~kg}{1.87\times 10^{18}~m^3}$
$\rho = 1240~kg/m^3$
The average density of Rhea is $1240~kg/m^3$.
