​Data:

m = 70kg.

g = 9.81 m/s^2

ρ = 1.275 kg/m^3

Cd = 1.10 (a flat rectangle)

​

My assumptions:

1. The main force of drag will be the diver's body which has dimensions 50cm by 70cm.

2. The terminal velocity is reached when the downward force of gravity equals the upward force from drag.

​

Fnet = Fg = Fd

mg = (1/2)ρA(Cd)v^2

(70)(9.81) = (1/2)(1.275)(0.5*0.7)(1.10)(v^2)

v^2 = 2797.86

v(terminal) = 52.9 m/s = 190.4 km/h