Mathematically, a rotation is a rigid body movement which, unlike a translation, keeps at least one point fixed. Main article: Rotation (mathematics) Rotation ( angular displacement) of a planar figure around a point Rotational orbit v spin Relations between rotation axis, plane of orbit and axial tilt (for Earth) Įither type of rotation is involved in a corresponding type of angular velocity (spin angular velocity and orbital angular velocity) and angular momentum (spin angular momentum and orbital angular momentum). The ends of the external axis of revolution can be called the orbital poles. In that case, the surface intersection of the internal spin axis can be called a pole for example, Earth's rotation defines the geographical poles.Ī rotation around a completely external axis is called a revolution (or orbit), e.g. The special case of a rotation with an internal axis passing through the body's own center of mass is known as a spin (or autorotation). A solid figure has an infinite number of possible axes and angles of rotation, including chaotic rotation (between arbitrary orientations), in contrast to rotation around a fixed axis.

A plane figure can rotate in either a clockwise or counterclockwise sense around a perpendicular axis intersecting anywhere inside or outside the figure at a center of rotation. Rotation or rotational motion is the circular movement of an object around a central line, known as axis of rotation. JSTOR ( March 2014) ( Learn how and when to remove this template message)Ī sphere rotating (spinning) about an axis.Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.

Rotations geometry rules