How much force would there be behind a punch coming from a 5'2" 15-year-old girl travelling at 761 miles per hour?
Enough that you're probably not going to be on khv any time soon. Never underestimate the power of PMS.
That's around the same speed that sound has in air. I doubt a human fist would sustain that speed without breaking or at least sustaining harm. But assuming it wouldn't, a punch at that speed would probably be like a less potent bullet, but with more mass. Idk lol.