3.) The following graph describes a bicycle racer's distance from a roadside television camera. Distance (in meters) s(t)↑ 1000 800- 600- 400 200 (10, 280) (100, 1000) 0 10 20 30 40 50 60 70 80 90 100 110 120 Time (in seconds) a. When is the bicyclist's velocity the greatest? How can you tell? b. Is the bicyclist's acceleration positive or negative? How can you tell?