In this diagram, as the ball is moving up the hill its gradually
gaining potential energy. Once it goes over the top, gravity allows it to gain velocity and it begins a free-fall. As it rounds
the curve, centripetal acceleration allows it to gain even more velocity. Once it reaches the first loop, acceleration stress
slows it down. However, when it reaches the top of the loop, centrifugal force (the force that drives a moving body away from
the center of rotation) adds to the cars kinetic energy, allowing it to make it back to the station where friction brings
it to a stop. Without all of the angles being exactly as they are, or all of these forces acting on it, the car would not
be able to make it back to the station.