Below are links to tutorials that take a deep dive into making things boingy. They are sorted from simple to complex so be prepared for some heavy duty math as you get near the bottom. If you want help with maths stuff, come see us on the DragonRuby Discord and head for the #math-physics channel.
Tutorials
Build a simple 2D physics engine for JavaScript games https://developer.ibm.com/tutorials/wa-build2dphysicsengine/
Collision Detection and Response https://www.metanetsoftware.com/technique/tutorialA.html
Newcastle University Game Engineering - Physics https://research.ncl.ac.uk/game/mastersdegree/gametechnologies/physicstutorials/
Rigid Body Dynamics http://www.chrishecker.com/Rigid_Body_Dynamics
Game Physics Series https://allenchou.net/game-physics-series/
References
These are the resources that almost everyone builds on. They can be tougher to learn from but it’s the most definitive information
Dirk Gregorius. March 2013. “The Separating Axis Test Between Convex Polyhedra.” Game Developers Conference. http://media.steampowered.com/apps/valve/2013/DGregorius_GDC2013.zip
Dirk Gregorius. March 2015. “Robust Contact Creation for Physics Simulations.” Game Developers Conference. http://media.steampowered.com/apps/valve/2015/DirkGregorius_Contacts.pdf
Erin Catto. GDC 2005. “Iterative Dynamics” https://box2d.org/files/ErinCatto_IterativeDynamicsSlides_GDC2005.pdf
Erin Catto. GDC 2006. “Fast and Simple Physics using Sequential Impulses” https://box2d.org/files/ErinCatto_SequentialImpulses_GDC2006.pdf