Box2D is a 2D physics engine for games.

Collision:
* Continuous collision detection
* Contact callbacks: begin, end, pre-solve, post-solve
* Convex polygons and circles
* Multiple shapes per body
* One-shot contact manifolds
* Dynamic tree broadphase
* Efficient pair management
* Fast broadphase AABB queries
* Collision groups and categories

Physics:
* Continuous physics with time of impact solver
* Persistent body-joint-contact graph
* Island solution and sleep management
* Contact, friction, and restitution
* Stable stacking with a linear-time solver
* Revolute, prismatic, distance, pulley, gear, mouse joint, other joint types
* Joint limits, motors, and friction
* Momentum decoupled position correction

WWW: https://box2d.org/