First, create an illustration of the motion of the two cars as shown in the attached picture. The essential equations used is
For constant acceleration:
a = v,final - v,initial /t
The solutions is as follows:
a = v,final - v,initial /t
3.8 = (v - 0)/2.8 s
v = 10.64 m/s
After 2.8 seconds, the speed of the blue car is 10.64 m/s.
For constant acceleration:
a = v,final - v,initial /t
The solutions is as follows:
a = v,final - v,initial /t
3.8 = (v - 0)/2.8 s
v = 10.64 m/s
After 2.8 seconds, the speed of the blue car is 10.64 m/s.