Part 2) The frictional force between the road and the tyres of a car are responsible for bringing the car to a stop. A car initially traveling at U,~ = 53 km/h in a northerly direction slams on its breaks and skids to a stop over a distance of d = 79.6 In. What is the average acceleration of the car over this time period? Pay attention to the sign in your answer. Part 3) What is the coefficient of kinetic friction between the tyres and the road? Interesting point: When a car's wheels continue to roll to bring it to a stop, the surface between the tyres and the road is stationary so static friction actually applies in this case, even though the car is moving. Because the coefficient of static friction is larger than the coefficient of kinetic friction, this means cars can stop more quickly if their wheels continue to roll. This is how ABS breaks work; they keep the wheels turning rather than allowing the car to skid