A team of astronauts is on a mission to land on and explore a large asteroid. In addition to collecting samples and performing experiments, one of their tasks is to demonstrate the concept of the escape speed by throwing rocks straight up at various initial speeds. Assume that the asteroid is approximately spherical, with an average density p = 2.28 X 106 g/m3 and volume V = 1.71 X 1012 m3. Recall that the universal gravitational constant is G = 6.67 X 10'11 N-mzlkgz. With what minimum initial speed Um will the rocks need to be thrown in order for them never to fall back to the asteroid? _ Um m/s