An athlete runs back and forth along a straight 200 m track following this time schedule:
• Runs in the forward direction with constant speed 4ms−1 for 10s.
• Comes to rest in the next 2s with uniform retardation.
• Immediately starts running back towards the starting point with constant speed 3ms−1 for 8s.
(i) Sketch the velocity–time graph for the entire motion, taking the forward direction as positive.
(ii) Calculate the magnitude of retardation while the athlete is coming to rest.
(iii) Find the net displacement of the athlete from the starting point at the end of the motion.
(iv) Determine the total distance travelled.
(v) Compute the average velocity for the complete run.