A 69 kg swimmer free-falls off a 10.0 m diving platform. The diver comes to a stop 2.7 m below the water's surface. What is the magnitude of the force exerted by the water on the swimmer. (assume a positive direction is up)

I calculated the force on the diver before they hit the water was 676.2 N, however, I am not sure how to calculate the resistance given from the water. Thank you.

mgh =mv²/2

v²= 2gh) = 2•9.8•10 =196 m²/s²
a=v²/2•s =196/2•2.7=36.3 m/s²
F(fr) = ma=69•36.3 =2504.7 N