Where is the positive acceleration for a roller coaster?

Positive acceleration for a roller coaster occurs when the coaster is speeding up, typically during descents or when it transitions from a slower section to a faster one, such as at the bottom of a hill or during a drop. This acceleration is felt by riders as an increase in speed, often enhancing the thrill of the ride. It can also occur when the coaster navigates tight turns or launches, where the forces push riders back into their seats.