At the moment car a is starting from rest and accelerating at 5.0 m/s2, car b passes it moving at a constant speed of 45m/s. how long will it take car a to catch up with car b?

X=v (initial) t+.5 (a) t^2. Car B's displacement can be represented by equation x=45t. Car A can be represented by the equation x=.5 (5) t^2. Plug these equations into a graphing calc and find intercept, the x value is time, the y is displacement.