A car starts from rest and accelerates uniformly at 3.0 m/s2 toward the north. A second car starts from rest 6.0 s later at the same point and accelerates uniformly at 5.0 m/s2 towar the north. How long after the second car starts does it overtake the irst car?
a. 12 s
b. 19 s
c. 21 s
d. 24 s
