If I throw a ball from a height, how can I describe the start-energy and the energy when it hits the ground?

I know it's potential or kinetic, but I need an explanation on why.

And how can I relate mgh=1/2mv^2 to this situation?

Question

If I throw a ball from a height, how can I describe the start-energy and the energy when it hits the ground? 

I know it's potential or kinetic, but I need an explanation on why. 

And how can I relate mgh=1/2mv^2 to this situation?

anonymous · Answer

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find potential/kinetic energy at point 1,2,3 seperately using equations of motion, total energy at a point is sum of potential and kinetic, at 1 energy is solely potential and at 3 is kinetic , no energy loss/gain implies mgh=mv2/3