It is true that energy will always be there. There are times when kinetic will turn into potential energy but it would just need another item that can turn it into kinetic energy.
The given example is a bouncing ball. If the ball’s energy will never change, it would continue bouncing for the rest of time. It does not bounce forever.
There are different things that may happen to it. When it is stopped, then it will not be able to bounce anymore. Most of the time, the energy from the bouncing ball can transform into different forms of energy.
"Energy Is the Ability to Do Work." Energy can be found in a number of different forms. It can be chemical energy, electrical energy, heat (thermal energy), light (radiant energy), mechanical energy, and nuclear energy. Stored and Moving Energy.