Falling cat problem

The falling cat problem is a problem that consists of explaining the underlying physics behind the observation of the cat righting reflex.

Although amusing and trivial to pose, the solution of the problem is not as straightforward as its statement would suggest. The apparent contradiction with the law of conservation of angular momentum is resolved because the cat is not a rigid body, but instead is permitted to change its shape during the fall owing to the cat's flexible backbone and non-functional collar-bone. The behavior of the cat is thus typical of the mechanics of deformable bodies.

Several explanations have been proposed for this phenomenon since the late 19th century:

• Cats rely on conservation of angular momentum.^[1]
• The rotation angle of the front body is larger than that of the rear body.^[2]
• The dynamics of the falling cat have been explained using the Udwadia–Kalaba equation.^[3]