Re: Last sentence is new
Bob Clark,
You're right, it does not make sense if one is discussing foam, but the writer was calculating the kinetic energy for a chunk of solid ice.
The quote is: "... assuming a conservative relative impact velocity of 457.2 m/s (2 x 750 fps used in the JSC analysis) ... If the debris was 28.7 kg, that would be the equivalent of a 500 lb safe hitting the wing at 365 mph."
Robert