Lesson 1, Topic 1
In Progress

Path length

Consider the motion of a car along a straight line. We choose the x-axis such that it coincides with the path of the van’s motion and origin of the axis as the point from where the van started moving. i.e, the van was at x=0 at t=0 (Fig. 1). Let P, Q and R represent the positions of the van at different instants of time. Consider two cases of motion. In the first case, the van moves from O to P. Then the distance moved by the van is OP=+360 m. This distance is called the path length traversed by the van. In the second case, the car moves from O to P and then moves back from P to Q. During this course of motion, the path length traversed is OP + PQ= +360 m + (+120 m) = +480 m. Path length is a scalar quantity-a quantity that has a magnitude only and no direction.