I gave an answer somewhere else (too many threads around to be sure where), but I’m expanding on that.
Some numbers first: considering an object moving ~80kft in one second, the bare minimum speed is 80kft/s or ~ 26.67 km/s (about Mach 78). This would need an infinite acceleration at the starting and ending points of the trajectory, but we can calculate also the minimum possible acceleration, which turns out to be a tad higher than 10000g and gives a peak speed in excess of 50 km/s (see Note 1). They are huge numbers.
1) There’s no way something macroscopic can move that fast in air without a big sonic boom and a big fireball (I cannot put numbers on ‘big’ ... Read even more
