Chapter 6, Problem 60P

On February 15, 2013, an asteroid moving at 19 km/s entered Earth’s atmosphere over Chelyabinsk. Russia, and exploded at an altitude of more than 20 km. This was the largest object known to have entered the atmosphere in over a century. The asteroid’s kinetic energy just before entering the atmosphere was estimated as the energy equivalent of 500 kilotons of the explosive TNT. (Kilotons [kt] and megatons [Mt] are energy units used to describe the explosive yields of nuclear weapons, and you’ll find the energy equivalent of 1 Mt in Appendix C). What was the approximate mass of the Chelyabinsk asteroid?