Give me three ways on how gravitational energy is produced.

Particle model to predict what will happen if a sharp object creates a hole in the soccer ball

The identities of substances are the same before and after which type of change

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?