Final answer:
A line graph is the best type of graph to model the speed of a roller coaster over the full two minutes of the ride.
Step-by-step explanation:
The best type of graph to model the speed of a roller coaster over the full two minutes it takes to complete the ride would be a line graph. A line graph is commonly used to show how one quantity changes in response to another, making it suitable for representing the change in speed over time. Each point on the graph would represent the speed of the roller coaster at a specific moment during the two-minute ride.