In a long distance race, Michael is running at 3.8 m/s and is 75 m behind Robert, who is running at a constant velocity of 4.2 m/s. If Michael accelerates at 0.15 m/s^2, how long will it take him to catch Robert
D=vi(delta)t + 1/2a(delta)t^2
The Attempt at a Solution
I know how to do this type of problem when the accelerating runner starts from a rest, but I have no idea where to go from here. I've tried framing the problem a bunch of different ways but nothing.