initially, the car is traveling at 5.0 m/s.
so, we know acceleration for changing velocity is :
a = (v-v)/t ..........(i)
where v is the final velocity
v is the initial velocity
t is the time taken to change velocity
Now, as per the question :
initial velocity, v=5.0 m/s
final velocity, v =11 m/s
time taken, t = 3 s
putting the values in equation (i),
a = ( 11-5 )/3
a = 2 m/s²
Therefore, a, after 3 s, is <em>2 m/s².</em>