Final answer:
Static friction is at work when a car slows down on a level road without skidding, allowing it to decelerate smoothly according to the coefficient of static friction between the tires and the road.
Step-by-step explanation:
When a car slows down on a level road without skidding, the type of friction acting on it is static friction. Static friction is responsible for preventing the tires from slipping on the road surface. In the absence of skidding, static friction can adjust its magnitude up to its maximum limit to ensure the car decelerates smoothly. The rate at which the car can decelerate—also referred to as the deceleration rate—depends on the coefficient of friction between the tires and the road surface.
According to physics principles, the maximum deceleration 'a' is given by a = μ * g, where μ is the coefficient of static friction, and g is the acceleration due to gravity (about 9.81 m/s² on Earth). A car with a mass 'm' decelerating at a rate 'a' will experience a net force 'F' equal to F = m * a, which is the static frictional force exerted by the road on the car.