n automobile traveling at a speed of 29.3 m/s applies its brakes and comes to a stop in 4.9 s. If the automobile has a mass of 1.2 103 kg, what is the average horizontal force exerted on it during braking? Assume the road is level.

magnitude N
direction

V = Vo + a*t

V = 0
Vo = 29.3 m/s
t = 4.9 s.
Solve for a. It will be negative.

F = M*a
Solve for F. It will be negative.