Final answer:
A fired rocket firework begins with stored chemical energy which is then converted into kinetic energy for propulsion. At its peak, the kinetic energy has been transformed into gravitational potential energy. As it falls back to the ground, this potential energy is converted back into kinetic energy.
Step-by-step explanation:
When a rocket firework is lit, the initial energy store is in the form of chemical energy brought about by the firework's propellant. As the firework ignites, this chemical energy is converted into kinetic energy, which propels the rocket upwards. As it reaches its peak altitude, much of the kinetic energy has been converted into gravitational potential energy. Finally, as the firework falls back to the ground, this gravitational potential energy is then converted back into kinetic energy as the firework speeds up towards the ground.
Learn more about Energy Store Changes