The mean diameters of X and Y, two planets in the same solar system, are 7.0 103 km and 1.4 104 km, respectively. The mass of X is 0.15 times the mass of Y. The value of g on Y is 8.6 m/s2.

(a) What is the ratio of the mean density of X to that of Y (ρX / ρY)?


(b) What is the value of g on X?
m/s2

(c) The mass of Y is 6.318 1024 kg. What is the escape speed on X?
m/s

1 answer

I've done a and b, but I can't figure c out. Do I use G=6.67e-11?