Sounds like we just need to find acceleration of the car:
v2^2 = v1^2 + 2ad
a = (v2^2 - v1^2) / 2d
a = (10.1^2 - 12.4^2) / 2(12)
a = -2.15625 m/s^2
This makes sense since the car is slowing down due to friction only, now find force:
F = ma
F = 1200(-2.15625)
F = -2587.5 N
Therefore, force of...