You are an astronaut, and you observe a small planet to be spherical. After landing on the planet, you set off, walk straightahead, and find yourself returning to your spaceship from theopposite side after completing a lap of 25 km. You hold a hammerand a falcon feather at a height of 1.4 m, release them, andobserve them to fall together to the surface in 29.2s. What is the mass of the planet?