I have a swimming pool which is 2m deep and was wandering whether I will be safe if I dive from 2nd floor which is around 4m high. [I'm 175cm tall and weigh 65kg]

Working out gravitational energy = mg = (65)*10 = 650

Equating to kinetic energy, (1/2)*(65)*v^2 = 650

v=4.47m/s.

I will be rounding my self like a ball so that my bottom hits the surface of the pool first with most impact creating resistance.

How am I going to get approx figures for drag coefficients and buoyancy and what are the such formulas for working out depth with them?

Help will be appreciated as I'm gonna be jumping off in the weekend