NEIEP Mechanics Practice Exam

If a car speed were 100 FPM, what should the stopping distance be?

1. 12 inches

2. 24 inches

3. 36 inches

4. 48 inches

The correct answer is: 24 inches

The stopping distance of a car is influenced by several factors, including its speed and the coefficient of friction between the tires and the surface. When dealing with stopping distances, a commonly referenced rule in mechanics indicates that, for every foot per minute (FPM) of speed, a vehicle should stop within a distance proportional to its speed. In this case, if a car is traveling at 100 FPM, it is generally estimated that the stopping distance should be twice the speed when considering an average stopping distance calculation. Therefore, 100 FPM would translate to a stopping distance of approximately 200% of that speed, which is equivalent to 24 inches. This estimation considers both the time it takes the driver to react and the distance required for the vehicle to come to a complete stop after the brakes are applied. The answer reflects a balance between reaction time and the engineering principles behind braking distances.