A satellite of mars, called phobos, has an orbital radius of 9.4 106 m and a period of 2.8 104 s. assuming the orbit is circular, determine the mass of mars.

The radius and time period of orbit of a sattellite are related by the formula:

R³ = GMT²/4π²; where R is the orbital radius, T is the orbital time period, M is the mass of the more massive body, G is the graviational constant

(9.4 x 10⁶) ³ = (6.674 * 10⁻¹¹) (M) (2.8 x 10 ⁴) ² / (4 π²)

M = 6.27 x 10²³ kg