f a roller coaster $($mass $=500$ kg$)$ starts from rest $50$ meters above the ground $($assuming no friction$),$

answer the following:

$50.$ Where is the potential energy the greatest?

a$.$ At the top$-$ of the first hill

b$.$ At the bottom of the hill

c$.$ Both the top of the hill and at the bottom of the hill have the same amount of

potential energy