Physics
posted by Tony .
The leader of a bicycle race is traveling with a constant velocity of +11.9 m/s and is 10.7 m ahead of the secondplace cyclist. The secondplace cyclist has a velocity of +9.10 m/s and an acceleration of +1.20 m/s2. How much time elapses before he catches the leader?

(v2•t+at²/2)  v1•t = 10.7
at²/2+ (v2v1)t 10.7 = 0
0.6t² 2.8t 10.7 =0
t= [2.8±√(2.8² +4•0.6•10.7)]/1.2.
The positive root is 7.16 s.