On february 15, 2013, a superbolide meteor (brighter than the sun) entered earth’s atmosphere over chelyabinsk, russia, and exploded at an altitude of 23.5 km. eyewitnesses could feel the intense heat from the fireball, and the blast wave from the explosion blew out windows in buildings. the blast wave took approximately 2 minutes 30 seconds to reach ground level. (a) what was the average velocity of the blast wave? (b) compare this with the speed of sound, which is 343 m/s at sea level.