Air Resistance of a Diver using Ek and Eg

1. The problem statement, all variables and given/known data
A 57.0 kg diver dives from a height of 15.0 m. She reaches a speed of 14.0 m/s just before entering the water. What was the average force of air resistance (e.g., friction) acting on the diver?
What is the force of friction underwater if she reaches a depth of 2.5 m before stopping? Do not neglect the buoyant force of 500 N acting on the diver once underwater

2. Relevant equations
Eg=mgh
Ek=(1/2)mv^2
Et=Ek+Eg
W=Ef-Ei
W=change in Ek
W=fd

3. The attempt at a solution
Ek=(1/2)(57kg)(14m/s)^2
=5586J

W=Ek
=5586J-0J

W=fd
5586J=F(15m)
5586/15=F
F=372.4N

Fnet=ma
=(57kg)(9.8N/kg)
=558.6N

Fnet=558.6N
Fapp-Ff=558.6N
372.4N-Ff=558.6N
Ff=186.2N

I’m not sure if I solved for friction properly. The way that I solved here doesn’t work for the next step in the water, so I think initially started wrong.

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