4000 fpm is basically impossible in free fall
It's only 45 MPH
Nigel, 5280 fpm is 60 MPH. A brick would be far higher than 120 MPH, which is what a skydiver in belly to earth falls at, on average, they use weights and tight/loose clothing to adjust free fall speeds relative to one another, Grand Slam and Tall Boy bombs of WWII impacted at some 750 MPH, only power required was an aircraft to drop them from.