A spaceship orbits Planet X at a distance of 1.5x107m from the planet's center. a) If the orbital period is 6 hours (21,600s), what is the mass of Planet X? b) If the spaceship wants to leave Planet X, what minimum speed is necessary to escape the gravity of planet X, (starting at the location of the original orbit, 1.5x107m from the planet's center and going FAR away)