Answer:
In the beginning, a roller coaster is still which means the forces acting upon the roller coaster are equal. But then as the rollar coaster starts to move upwards, the potential energy changes into kinetic energy since it is in motion. When the roller coaster reaches the top and stops, its kinetic energy immeadiately transforms into potential energy because it has potential to move and go fast. As the roller coaster descends, the potential energy transforms into kinetic energy. Hope this helps!
Step-by-step explanation: