INTRODUCTION

We have already discussed in chapter 17 linear motion or motion of translation. And we have also discussed in the last chapter motion of rotation. But sometimes a body has, simultaneously, a motion of rotation as well as translation such as wheel of a car, a sphere rolling (without slipping) on the ground etc. A little consideration will show, that such a motion will have the combined effect of rotation as well as translation. Now in this chapter, we shall discuss the combined motion of rotation and translation.

MOTION OF A RIGID LINK

Consider a rigid link AB, which moves from its initial position AB to its final position A1B1. It will be interesting to know that the link neither has, wholly a motion of translation nor wholly

rotational, but a combination of the two. But the point B moves faster than the point A as shown in Fig. 22.1. (a).

INSTANTANEOUS CENTRE