Educator

Mathematically, a rotation is a rigid body movement which, unlike a translation, keeps a point fixed. This definition applies to rotations within both two and three dimensions (in a plane and in space, respectively.) A rotation in three-dimensional space keeps an entire line fixed, i.e. a rotation in three-dimensional space is a rotation around an axis. This follows from Euler's rotation theorem.All rigid body movements are rotations, translations, or combinations of the two.A Rotation is simply a progressive radial orientation to a common point. That common point lies within the axis of that motion. The axis is 90 degrees perpendicular to the plane of the motion. If the axis of the rotation lay external of the body in question then the body is said to Orbit. There is no fundamental difference between a \“rotation\” and a \“orbit\” and or spin. The key distinction is simply where the axis of the rotation lay, either within or without a body in question. This distinction is and can be demonstrated in and for both \“ridged\” and \“non ridged\” bodies.