Answer :
So we need to name a situation where gravitational potential energy might be usefill and one situation where it might be harmfull. First, gravitational potetnial energy is the energy that is stored in a body because of its posititon in a gravitational field. It can be usefull in producing hydropower because it can be transfered into kinetic energy of the water to power generators who then produce electrical energy. It can be harmfull to somebody who is standing on a cliff or a high place because if he falls down, his gravitational potential energy turns into kinetic energy and he can hit the ground with very high velocity which can produce injuries or even death.
