Simple orbital collision problem -- need help!

[johnb]

(10-08-2023 06:03 PM)johnb Wrote:  1. Let's assume the likely apogee of a transcontinental suborbital passenger flight is 100 km. (Can we use 110 km to get more impressive numbers, or is that stretching things?) What's a simple model for the horizontal speed at apogee? (And what's the value?)

Am I being super-dense here in not assuming that the flight is a parabola (which would probably mean the horizontal speed at apogee is negligible)?