INTRODUCTION TO MOTION IN A PLANE
In the last chapter we developed the concepts of position, displacement, velocity and acceleration that are needed to describe the motion of an object along a straight line. We found that the directional aspect of these quantities can be taken care of by + and – signs, as in one dimension only two directions are possible.But in order to describe motion of an object in two dimensions (a plane) or three dimensions (space), we need to use vectors to describe the above- mentioned physical quantities.Therefore,it is first necessary to learn the language of vectors. What is a vector ? How to add, subtract and multiply vectors ? What is the result of multiplying a vector by a real number ? We shall learn this to enable us to use vectors for defining velocity and acceleration in a plane. We then discuss motion of an object in a plane. As a simple case of motion in a plane, we shall discuss motion with constant acceleration and treat in detail the projectile motion.Circular motion is a familiar class of motion that has a special significance in daily-life situations. We shall discuss uniform circular motion in some detail.
The equations developed in this chapter for motion in a plane can be easily extended to the case of three dimensions.