A NASA satellite has just observed an asteroid that is on a collision course with the Earth. The asteroid has an estimated mass, based on its size, of 5x10^9 {kg}. It is approaching the Earth on a head-on course with a velocity of 710 {m/s} relative to the Earth and is now 4.5×10^6 {km} away.
With what speed will it hit the Earth's surface, neglecting friction with the atmosphere?