Answer:
4000 N
Explanation:
According to Newton's second law, a resultant force is equal to mass times acceleration. i.e
[tex]F_{net} = ma = 800 kg * 5 m/s^{2} = 4000 N[/tex]
So assuming that there is no other force that is acting on this car, a force of 4000 N would cause the acceleration mentioned in the question.