Final answer:
The feet of stopping distance for a vehicle traveling at 40 mph can be calculated by adding the distance covered during the driver's reaction time to the distance needed to bring the vehicle to a complete stop. However, exact calculations require specific values for road conditions, friction, and reaction time.
Step-by-step explanation:
The question of how many feet of stopping distance a vehicle requires when driving at 40 mph involves several variables, including the condition of the road (dry or wet pavement), the coefficient of friction between the tires and the road, and the driver's reaction time.
To calculate this distance, one must consider the vehicle's speed and braking capabilities. The distance covered during the driver's reaction time, which is typically around 0.500 seconds, must be added to the stopping distance—the time it takes for the vehicle to come to a complete stop after the brakes are applied.
For example, if a vehicle traveling at 30.0 m/s (which is approximately 67 mph) requires a specific stopping distance, a vehicle traveling at 40 mph (which is slower) would need less distance to stop. However, without specific values for the coefficient of friction and other factors for the 40 mph scenario, we cannot provide an exact number.
Still, the method includes recording the time it takes to stop from 50 mph, which can be used as a reference to estimate the stopping distance at different speeds with proper scaling.
The total stopping distance will be the sum of the distance covered during the driver's reaction time plus the distance taken to stop the vehicle once the brakes are fully applied.