A school athlete runs three complete laps around a circular track of radius 80m in 6minutes. Immediately after finishing the third lap, he walks straight across the field along a diameter of the same track in 40s and halts.
(i) Compute the total distance travelled.
(ii) Find the magnitude of the total displacement from the starting point to the final point.
(iii) Calculate the average speed for the whole motion.
(iv) Calculate the average velocity (magnitude) for the whole motion.
(v) If the athlete had run only two and a half laps before walking across the diameter (with the running time in the same ratio as the distance covered), would the average velocity be greater, smaller or equal to the value found in part (iv)? Justify qualitatively without further calculation.