Question

If the roller coaster track has a hill at the end that was equal in height to the original hill, would the marble make it all the way to the top?

Please explain it to me!
Thanks.

Answer 1

not quite

any energy lost to friction or air resistance would prevent it from having enough energy to make it back to the same height (unless it started with a big push)
If not moving at start, total energy = potential energy = m g h
if any energy is lost during the trip, it will not be able to muster m g h once it stops again if h is the original h