Question

In order for rollercoaster to work, why does the hill the cart climbs need to be higher than the top of the loop?

Answer 1

For momentum purposes. The roller coaster needs to be going fast enough to make it all the way around the loop without being assisted by the tracks

Answer 2

Answer:

"At the top of the first and tallest hill, your potential energy is at its highest it will ever be on this ride. As you begin to descend, your potential energy decreases until it's all gone at the bottom of the hill." The shorter the hill the roller coaster climbs, the greater its kinetic energy.