A 1100 kg car accelerates from rest to 60.0 km/h over a distance of 45 m. Find the net force acting on the car.

$60.0\mathrm{km/h} \fallingdotseq 16.667\mathrm{m/s}$

I wanna use the Newton's equation of motion "$F=ma$". However, the accelerarion is unknown.

So, firstly, I find the accelaration of the car.

Let F, a, m be the net force , acceleration and mass of the car respectively. Then, assume that the car is moving with constant acceleration. Because the initial and end velocity are given, a following formula (*) of constant acceleration movement is allowed.

$$v^{2}-v_{0}^{2}=2ax\:\:\:\:\:\:\:(*)$$

$x$ is the distance that traveled by the car.

Solving that formula, you can find the acceleration of the car.

Finally, using Newton's equation of motion, you can find the net force F.