You first would have to find the Gravitational Potential Energy of the coconut. This can be done by multiplying PE=mgh PE=(1)(9.81)(3) PE=29.43.
However, in order to find the KE of the coconut, you would need to specify on when in the coconuts fall you would like to know the KE.
For example, at the top of the tree, before it falls, the coconut has PE of 29.43J but KE of 0J. When the coconut is about to hit the ground, though, the coconut will have a KE of 29.43J and PE of 0J.
This is because of the Law of Conservation of Energy which states that energy is not created if destroyed.
In this system, PE is converted to KE and so at the end of the fall, the coconut has the same KE as the PE it had in the beginning.
