What kind of energy does it take for loops on roller coasters to work?

Loops on Roller Coasters primarily rely on gravitational potential energy and kinetic energy. As the coaster climbs to the top of a loop, it gains gravitational potential energy, which is converted to kinetic energy as it descends. The speed and momentum generated during the descent enable the coaster to maintain enough energy to successfully navigate the loop without falling off. Additionally, factors like friction and the design of the loop play roles in ensuring a smooth ride.