The Mechanical Gyrocompass

Abstract

We are of course all familiar with examples of spinning bodies: from a child’s spinning top to the spinning earth and heavenly bodies in general. Such a body spinning freely in space will continue doing so indefinitely about a fixed axis; indeed the absence of any obvious forces of interaction between the parts of such a body must have convinced the ancients that the circular motion is “natural” and involves no forces. In fact the dynamical behavior of rotating bodies provides proof of the correctness within human experience of Newton’s laws of motion and the role of forces; Newton’s theory fully describes the often unintuitive dynamics of spinning bodies.