Game physics refers to the simulation of physical systems in a video game. This includes calculating the movements and interactions of objects, simulating forces like gravity and friction, and creating realistic collisions and reactions. The purpose of game physics is to make the virtual world of the game feel more believable and immersive.

There are several techniques used in game physics, including:

1. Rigid Body Dynamics: This simulates the physical movements and interactions of solid objects in a game. It includes calculating how objects rotate, collide, and react to forces like gravity and collisions.

2. Collision Detection: This is the process of determining when two or more objects in a game come into contact with each other. It involves calculating intersections between bounding volumes or more complex shapes to detect collisions accurately.

3. Particle Systems: Particle systems are used in games to simulate phenomena like fire, smoke, explosions, or other effects. They involve creating and animating a large number of small particles to create realistic and visually appealing effects.

4. Character Animation: Character animation involves creating and manipulating the movements of characters in a game. Techniques like inverse kinematics, skeletal animation, and motion capture are used to create realistic and fluid character movements.

5. Cloth Simulation: Cloth simulation is used to animate virtual garments or fabrics in a game. It involves simulating the physical properties of cloth, such as stretching, bending, and tearing, to create realistic cloth movements.

Game physics can be implemented using various libraries and engines, such as PhysX, Havok, or Box2D. These libraries provide pre-built algorithms and functions for simulating physics and can help simplify the implementation process for game developers.

Overall, game physics and animation are crucial aspects of game development that help create more immersive and realistic virtual worlds. They enhance the gameplay experience and make the game feel more interactive and believable for players.