of rocks (http://geology.about.com/cs/rock_types/a/aarockspecgrav.htm), use a relative density of 2.6 for the rock. First calculate the velocity of the ejected material [ 275 ] . Note Escape velocity (http://en.wikipedia.org/wiki/Escape_velocity) from Earth is 11.2km/sec. The velocity of the ejecta would have a wide distribution. It's reasonable to expect that some of it would be