​Data:

m = 70kg.

g = 9.81 m/s^2

ρ = 1.275 kg/m^3

Cd = 0.82 (a long cylinder)

​

My assumptions:

1. The main force of drag will be the diver's head and hips which I estimated to have a radius of 30cm

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

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Fnet = Fg = Fd

mg = (1/2)ρA(Cd)v^2

(70)(9.81) = (1/2)(1.275)(pi*0.3^2)(0.82)(v^2)

v^2 = 4646.02

v(terminal) = 68.2 m/s = 245.4 km/h