Rocket League, developed by Psyonix (now a part of Epic Games), utilizes Unreal Engine 3. Unreal Engine is a popular choice among developers for its versatility and powerful features that facilitate both simple and complex game development.
Unreal Engine 3 is a complete game development framework that provides a wide range of tools and capabilities, including realistic graphics, physics simulation, artificial intelligence, audio, and networking. It's known for its scalability across platforms, which allowed Rocket League to release on multiple consoles and PCs.
As an example, the physics engine in Unreal Engine 3 would handle something like the ball physics in Rocket League. Here's a simplistic pseudo code snippet to illustrate how this might work:
Of course, the actual physics in Rocket League would be much more complex, taking into account things like friction, air resistance, and collisions with cars and the environment.