By how much does stopping distance change when speed is doubled?

When speed is doubled, the stopping distance increases by a factor of four. This is primarily due to the fundamental physics of motion and the relationship between speed, distance, and time.

The stopping distance of a vehicle is influenced by two main components: reaction distance and braking distance. When a vehicle is traveling at a higher speed, the time it takes for the driver to react remains relatively constant, but the distance traveled during this reaction time will be greater since speed is higher. After applying the brakes, the braking distance also increases with the square of the speed due to the kinetic energy of the vehicle. Kinetic energy increases with the square of the velocity (speed), meaning that if you double the speed, the energy becomes four times greater. Consequently, it requires more distance to come to a complete stop.

This concept is critical for safe driving practices, highlighting the importance of maintaining appropriate speeds for the conditions and understanding how speed influences stopping distances.