A sportsman runs around a circular track of radius r and traverses the path ABAB as shown in the original figure. The distance travelled and the magnitude of displacement respectively are:

Question

G1 Physics · Accepted Answer

From the path shown, the sportsman covers one complete circumference and then one additional semicircle. Distance travelled: d = 2πr + πr = 3πr. The initial point is A and the final point is B. A and B are diametrically opposite points, so the straight-line displacement magnitude is the diameter: |Δr| = 2r. Therefore the required pair is 3πr, 2r. Correct option: D.