Project 11: Part A: Engineering a movie stunt

You and your team have been hired by Marvel Entertainment to develop a stunt for the next Black Panther movie.

In a scene meant to take place in T'Challa's homeland of Wakanda, a young T'Challa is searching for vibranium (Wakanda's chief export) on a large hill. While digging, he disturbs a large boulder, which begins to roll down the hill after him. In the scene, T'Challa is meant to sprint down the mountain while the boulder rolls behind him, catching up, but not running over T'Challa.

The production studio has designed several boulders (some solid spheres, some hollow spheres, and some cylindrical ones) for the stunt, but doesn't want to manufacture and ship all of them to the set. Also, they have yet to choose a stunt person because they aren't sure how fast that person will need to run down the hill. They've asked your team to design the stunt including the hill and to produce a graph that demonstrates how the speed of the boulder will change as it rolls down the hill. It's foam, but it's big.

Remember this is Hollywood, so make sure the stunt is exciting!