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 5Ă—10^9 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
6.0Ă—106 km away.
With what speed will it hit the Earth's surface, neglecting
friction with the atmosphere?
Express your answer using two significant figures.