1. A car is traveling at 15 meters/second on a horizontal road. The brakes are applied and the car sids to a stop in 4 seconds. The coefficient of kinetic friction between the tires and the road is 2. Coefficient of kinetic friction = friction / Normal Force 3. Time to stop / Velocity = 4/15 = .2666. The correct answer is roughly .38, but I have no idea on how to arrive at that.