An automobile moving at a constant velocity of 15 m/s passes a gasoline station. Two seconds later, another automobile leaves the station and accelerates at a constant rate of 2 m/s^2 in the same direction as the 1st automobile.

Question

How soon does the 2nd automobile overtake the first?

Answer 1

d1 = 15m/s * 2s. = 30 m head start.

d2 = 0.5a*t^2 = 30 + 15t
1*t^2 = 30 + 15t
t^2 - 15t = 30
t^2 - 15t - 30 = 0
Use Quadratic Formula and get:
t = 16.79 s.