A Physics Engine is a software component that simulates physical systems in a virtual environment. It calculates how objects interact based on the laws of physics, such as gravity, friction, and collision. This technology is commonly used in video games, animations, and simulations to create realistic movements and behaviors of objects. By using a Physics Engine, developers can create more immersive experiences for users. For example, when a character jumps or a car crashes, the engine ensures that these actions appear natural and believable. Popular examples of physics engines include Havok, Unity's PhysX, and Bullet.