KINEMATICS OF MOTION

Introduction
We have discussed in the previous Chapter, that the subject of Theory of Machines deals with the motion and forces acting on the parts (or links) of a machine. In this chapter, we shall first discuss the kinematics of motion i.e. the relative motion of bodies without
consideration of the forces causing the motion. In other words, kinematics deal with the
geometry of motion and concepts like displacement, velocity and acceleration considered as
functions of time.

Plane Motion
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.

Rectilinear Motion
It is the simplest type of motion and is along a straight line path. Such a motion is also known as translatory motion.

Curvilinear 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 (about the axis of rotation perpendicular to the plane of motion) such as a pulley rotating about a fixed shaft or a shaft rotating about its own axis, then the motion is said to be a plane rotational motion.