Q: Given a scientific passage and an answer, generate a question for the given answer.
Passage: Imagine the thrill of riding on a roller coaster like this one! The coaster slowly crawls to the top of the track and then flies down the other side. It also zooms around twists and turns at breakneck speeds. These changes in speed and direction are what make a roller coaster ride so exciting. Changes in speed or direction are called acceleration. Answer: acceleration
A:
What is the term for changes in speed or direction, changes that make a roller coaster ride so exciting?