Below is a selection of some random projects I did in junior college. I didn't do any real research or big projects after this, so it abruptly ends with Calculus III/Differential Equations.
Applied Project: Roller Derby (LaTeX source) for Calculus 3, which involved tying together the concepts of moments of inertia of different shapes with conservation of energy in order to determine what shape will roll to the bottom of a slope fastest in a race. The original questions for the project are not provided, but the paper is self-explanatory, assuming you're familiar with calculus. (Project was written in May 2022, and rewritten in LaTex in July 2022.)
Modeling the Dynamics of the Internet Platform Users' Volume (LaTeX source, BibTeX citations) for Differential Equations, which explains a particular model for the two groups of users on a two-party internet platform (such as Amazon or eBay) and how the two interact. The project this is based on can be found at SIMIODE here. (Written in April 2023.)