Pedro21

Hmm, the pressure acting upon entry will be, using the Bernoullis equation, rho*v^2/2. So if you decelerate to 60kph =~ 17mps it would be around 140kPa of pressure, due to your velocity, ignoring any aero/hydrodynamics. The force acting on the entering surface will be F=p*A, so the smaller the area the smaller the force, intuitively. Lets say you enter with 100cm2 area which gives us approx. 1400N of force. This means, entering water at 60kph with 100cm2 of impact area ignoring any hydrodynamics creates a force of 1400N, which is like letting a 140kg(308lb) man sit on your feet But, as soon as you start receiving it it will start decreasing, due to the fact that the water only reacts to your penetration velocity which decreases differentially. But your body will need to absorb that energy somehow, so your joints, spine, bones will have to process it. You are going to need to "squat" that 300lbs So even at 60kph the fall looks quite dangerous. And the depth that you might reach. I had an excel macro for this kind of things, namely a bullet entering water, but I am not at my PC right now. This is the last part, the depth