Kinematics of Motion:
Kinematics deals with the geometry of motion and concepts like displacement, velocity, and acceleration considered functions of time.
When the motion of a body is confined to only one plane, the motion is said to be plane motion. The plane motion may be either rectilinear or curvilinear.
It is the simplest type of motion and is along s straight line path. Such a motion is also known as Translatory Motion.
It is the motion along a curved path. Such a motion, when confined to one plane is called plane curvilinear motion.
When all the particles of a body travel in concentric circular paths of constant radii such as a pulley rotating about a fixed shaft rotating about its own axis, then the motion is said to be a plane rotational motion.