In order to find the energy stored by the car, let's use the formula below:
Where E is the electrical energy, Q is the charge and V is the potential difference (voltage).
So, for Q = 15.4 C and V = 9.16 * 10^8 V, we have:
Now, converting this energy into kinetic energy, we have:
Therefore, putting the answer with 3 significant digits, the velocity of the car would be 3980 m/s.