Impulse, Linear momentum belly flop

[rmunoz]

Homework Statement

Until he was in his seventies, Henri LaMothe excited audiences by belly-flopping from a height of 10 m into 31 cm. of water. Assuming that he stops just as he reaches the bottom of the water and estimating his mass to be 80 kg, find the magnitudes of the impulse on him from the water.

Homework Equations

J$$\rightarrow$$=$$\Delta$$P=Pf-Pi
J$$\rightarrow$$=$$\int$$F(t)dt
J=Favg * $$\Delta$$t

Question:
What is the best way to approach my first impulse problem aka, how do i go about solving for the following in the most efficient manner possible?
-Velocity before collision
-Time for the collision to occur
-Change in linear momentum aka Impulse

I would like to make sure i start this section off with the right methodology on the most basic problem, that way I can carry that knowledge on throughout the rest of the homework.

 

[rmunoz]

Help?