Suppose an Olympic diver who weighs 52.0 kg executes a straight dive from a 10m platform. At the apex of the dive, the diver is 10.8m above the surface of the water.
a) What is the potential energy of the diver at the apex of the dive, relative to the surface of the water?
b) Assuming that all potential energy of the diver is converted into kinetic energy at the surface of the water, at what speed in m/s will the diver enter the water?
c) Does the diver do work on entering the water? Explain.

a) Use E_p = mgh

b) Use E_k = \frac12 mv^2

c) What do you think about that?