Which formula correctly describes stopping distance?

The correct formula that describes stopping distance is based on the sum of thinking distance and braking distance. Stopping distance is defined as the total distance a vehicle travels from the moment a driver decides to stop until the vehicle comes to a complete stop.

Thinking distance refers to the distance a vehicle travels during the driver's reaction time, which is the time it takes to perceive a need to stop and then physically apply the brakes. This distance is dependent on the speed of the vehicle and the reaction time of the driver.

Braking distance is the distance the vehicle travels while it is decelerating after the brakes have been applied until it comes to a complete stop. This distance is influenced by several factors, including the vehicle's initial speed, road conditions, and the efficiency of the braking system.

By combining these two components, thinking distance and braking distance, one can accurately determine the total stopping distance. This relationship is critical for understanding how quickly a vehicle can stop and is essential for safe driving practices, particularly in emergency situations or when encountering sudden obstacles on the road.