A car is moving without sliding means that the friction between wheels and the ground is static friction. This is the force causing an object to move forward, therefore, its direction is the same as the moving direction of the car.
My question is: For the horizontal forces acting on any moving(without sliding) car, $\ F_{fs}$ always oriented forward, what's the backward force to balance $\ F_{fs}$ so as to keep the car moving uniformly? Is that the Force produced by engines?
Just to clarify, I am referring to auto cars (with engines).
Any help or thoughts are appreciated!!!