
Answer:
The acceleration of the car is 7.85 m/s²
Explanation:
Given;
vx(t)= (0.910m/s³)t², given time traveled by the car 't' = 5.0 s
⇒To determine the velocity for 5 seconds, we substitute in 5.0 s for t
vx(5)= (0.910m/s³)(5s)²
    = (0.910m/s³)(25s²)
   vx = 22.75 m/s
⇒To determine the acceleration of the car when vx=12.0m/s
Acceleration is change in velocity per unit time
when vx=12.0m/s, our new equation becomes; 12 = (0.910m/s³)t²
Solving for t: t² = 12/0.91
           t² = 13.187
           t = √13.187 = 3.63 s
 Acceleration = Δv/Δt
            [tex]= \frac{(22.75 - 12)m/s}{(5-3.63)s} = (\frac{10.75}{1.37}).\frac{m}{s^2}[/tex]
 Acceleration = 7.85 m/s²