Two cars, starting from rest at x=0 at t=0, are racing. Car A and B both accelerate in a straight line at a constant acceleration (a=4m/s2) for 10s. After 10s Car A stops accelerating (acceleration is 0m/s2), but Car B continues to accelerate at the same rate (a=4m/s2).
After 20s, Car B crosses the finish line. How far is the finish line from the starting point of the race?
D=_______________
How far behind is Car A when Car B crosses the finish line?