Rigid body

A rigid body is an object that doesn't change its shape or size, regardless of the forces acting on it. In physics, this concept helps us understand how objects move and interact. For example, when a solid ball rolls, all parts of the ball stay the same distance from each other, even as it moves. Rigid bodies are idealized models because most materials can deform slightly under extreme conditions, but for many practical purposes—like engineering and mechanics—assuming that objects are rigid simplifies calculations and helps predict their behavior in various situations.