~25mph assuming a Cd of 2.1 (a smooth brick is the closest I could find) a mass of 0.194Kg and a surface area of 0.01142313m^2 (75.6mm x 150.9mm).
Of course that assumes it’s falling facing its largest surface, and not tumbling or a falling edge first. Obviously that is trickier to calculate, but 20-40mph doesn’t seem that unreasonable.
Edit: it takes ~3 seconds to reach 99% terminal velocity.
Of course that assumes it’s falling facing its largest surface, and not tumbling or a falling edge first. Obviously that is trickier to calculate, but 20-40mph doesn’t seem that unreasonable.
Edit: it takes ~3 seconds to reach 99% terminal velocity.