Rigid Motion

Rotation, Reflection and Translation  are types of motion classified as rigid motion .A body is said to be in rotational motion if it rotates with respect to an axis passing through it .If a body is moved from one position to another, and if the lines joining the initial and final points of each of the points of the body are a set of parallel straight lines of length ℓ, so that the orientation of the body in space is unaltered, the displacement is called a translation parallel to the direction of the lines, through a distance ℓ.