A toy car is placed on a wooden plank that has a rough surface. If the car is pushed gently, it slides down the plank due to gravity. Which factor primarily affects how far the car will slide before coming to a stop?

The distance the car travels is mainly controlled by the friction between the car’s wheels and the rough plank, which is measured by the coefficient of friction. When the coefficient is high, the friction force is larger, so the car slows down more quickly and slides a shorter distance. If the coefficient is low, the friction force is weaker, the car keeps moving farther before stopping. For instance, a car on a plank with a low coefficient of friction will glide almost twice as far as one on a rougher surface with a higher coefficient. Thus, the coefficient of friction is the key factor determining the sliding distance.