First, we find the acceleration of the car using the following formula.
![v_f=v_0+at](https://img.qammunity.org/2023/formulas/physics/college/qgre38q8sgm0h17jd2cw9z9w3fnmh5ftbi.png)
Where the final speed is zero (because the car stops), the initial speed is 86.55 km/h, and the time is 4.163 seconds. Let's replace these magnitudes and solve for a.
![\begin{gathered} 0=86.55((km)/(h))+a\cdot4.163\sec \\ -86.55((km)/(h))=a\cdot4.163\sec \\ a=(-86.55((km)/(h)))/(4.163\sec ) \end{gathered}](https://img.qammunity.org/2023/formulas/physics/high-school/eeset1p5wgivx2qb4ful4gntee17wm2v9t.png)
But, we have to transform the speed from km/h to m/s.
![\frac{86.55\operatorname{km}}{h}\cdot\frac{1000m}{1\operatorname{km}}\cdot(1h)/(3600\sec )\approx24.04((m)/(s))]()
Then, we use this transformation to find the acceleration.
![\begin{gathered} a=(-24.04((m)/(s)))/(4.163\sec ) \\ a\approx5.77((m)/(s^2)) \end{gathered}](https://img.qammunity.org/2023/formulas/physics/high-school/ks9ggyp6rfebthxqcupflk54zfy2vl578m.png)
Once we have the acceleration, we can use Newton's Second Law to find the net force.
![F=ma](https://img.qammunity.org/2023/formulas/physics/high-school/f29csqfwijobd1j24f6y6vv1aba7x8qmg1.png)
Let's replace the mass and acceleration to find F.
![\begin{gathered} F=1066\operatorname{kg}\cdot5.77((m)/(s^2)) \\ F=6150.82N \end{gathered}]()
Therefore, the net force on the car is 6150.82 Newtons.