Nah, it's ok.
If you ask me, the drag is maybe more unrealistic. When I deorbit my second stage, even when it has a payload and tonnes of fuel on board, its velocity goes from 1200 m/s at 10,000 m to 50 m/s by the time it gets to 1000 m, just because of drag, whichs seems kind of extreme......
But in real life, you'd add a 0 to that number, right?
1000 mph.
Nah, I've been reading around in unrelated stuff about the recovered drone sections from spaceX boosters. Apparently they're only doing 160m/s when they start the hoverslam burns.
Drag is hideous stuff, an F1 car generates 1g of decelerating force just by the driver taking his foot off the accelerator. That's equal to a driver in a road car slamming hard on the actual brakes.
Not sure. The speed of sound is "only" 340 m/s, no object could remain supersonic on a long time without propulsion (especially if it's not aerodynamically shaped).
But an object that would slow down so fast would most likely desintegrate itself indeed.
There's no general answer to that, but 50 m/s is not that slow: it's approximately the limit speed that could reach a human in free fall. It's a matter of aerodynamics, but also of mechanical and/or thermal resistance.
And the speed of sound is a relative term. It's different at altitude to sea level, temperatures, barometric pressures and even in different objects (it's like 900ish in water and several thousand through solid objects). The denser the medium, the faster sound travels.
When Felix set the freefall records a few years back, he went from 0 to over Mach 1 and back down to a standard freefall speed without aids (apart from a space suit) without disintegrating.
But then you look at incoming meteorites. They arrive too fast, at the wrong angle and they tend to explode, flattening large areas like an airbursting bomb.