Okay, I got this worksheet today and my teacher didn't explain to me what shock cones were. So here's the problems, and what I did so far to work them out. "An aircraft makes a supersonic pass 382 m over an observer. the shock wave pounds the observer after the plane is 405 m past her position (line of sight). what was the aircraft's ground speed if the flight path was level and the air temperature was 16 degrees Celsius?" I started out by doing the speed of sound using the temperature correction formula, 331 + 0.6T, to get 340.6 m/s as the speed of sound. But now I am stuck as to how to find the ground speed of the plane. This one, I have no clue on, so any hints will help. "A light cone of 30 degrees is observed in crown glass which allows light to travel at 2.0 x 10^8 m/s. How fast was the particle supposedly going? Then find the real maximum light cone angle for a relativistically allowed velocity in this glass."