Hi again! So, this time I have a ball with a mass m that I throw down from some point with a height h. I want to write the kinetic and potentiel energies that the ball has in the start and in the end for this ball that is falling to h=0. What I have thought of is that the ball must have a potential energy, u = mgh before it is thrown and when it hits the grown, and when it's moving down the energy is kinetic. I dont understand completely why and when it's undergoing a certain form of energy. How does mgh=1/2mv^2 relate to this situation? In my notes I also have that E = mgh + 1/2mv2 , which for some reason is the start energy?