A racer has just completed his first lap at a speed of 198m/s. Now his speed decrease or he decelerateted at 195m/s after 2s of his completion of first lap, as soon as he saw a curve path(line segment R). He then moved at a constant speed of 195m/s for the next 2s(line segment s). Then the race track after 4s of the completion of first lap was straight, so the racer accelerated to 200m/s within 2s( line segment T) and traveled at a constant speed for the next 6s( line segment U). After 12s from the first lap completion, he immediately saw a curve track, so he decelerateted to the speed of 194m/s within 3s( line segment V).
