How can i measure the acceleration of wooden cars being rolled down a hill?

For our science fair my project is the “the effect of the shape of a car on the aerodynamics” and my adult sponsor said, “its not enough to build models and time their speed down a hill, like the pine wood derby… you have to find a way to measure the acceleration of the models down the hill.” I’m in 9th grade so i haven’t taken physics yet. can somebody help me figure this out? i read like 20 articles on Wikipedia and totally confused myself.