Unsolvable? Kinematics - Constant deceleration and friction Here's the way the problem is laid out: A car travels at 52.4 km/hr on a flat highway. If the coefficient of kinetic friction is 0.151, what is the minimum distance needed for the car to stop? Given: Vi = 52.4 km/hr (calculated as 14.555(...) m/s) Vf = 0 m/s muk= 0.151 g = 9.81 m/s2 Unknown: /\ x, /\ t, a, m It seems to me that I have too many missing variables to solve the problem. I know that Vavg = (Vi + Vf)/2, so the average velocity would be around 7. 277 m/s, but without /\t, I can't carry out any of the normal kinematic equations to find /\x, and without m, I can't figure out Fk, Fg, or FN. Is there something I'm missing, or is the problem actually unsolvable?