I just spent a while looking up the maths on this and was really surprised to find that the terminal velocity of a spherical rock (diameter 10cm, density 2.5g/c

I just spent a while looking up the maths on this and was really surprised to find that the terminal velocity of a spherical rock (diameter 10cm, density 2.5g/cm^3) at this altitude is remarkably close to 300 km/h (I got 340). Aside: up until now I had imagined that if a skydiver were to ever drop a rock of that size (or a dense piece of equipment like a DSLR) during freefall they would never be able to catch it, but as the terminal velocity of a skydiver in "dart" position is about 320km/h that's not the case. Pretty cool.