Answer :
Final answer:
The stopping distance for a fully loaded truck at 55 mph can exceed 1000 feet due to factors like driver's reaction time and vehicle's kinetic energy. The option of more than 1800 feet may be a conservative estimate for such a scenario, highlighting the importance of safe driving practices for heavy vehicles on highways.
Explanation:
The question relates to the stopping distance of a fully loaded truck traveling at 55 mph. To accurately determine the stopping distance, one must consider both the reaction time of the driver and the physical stopping time of the truck. Reaction time is the interval between the driver perceiving a need to stop and actually starting to apply the brakes. The stopping time, or braking distance, depends on factors like the truck's weight, the condition of the brakes, road surface, and whether the truck is on a slope. Given no specifics on reaction time or conditions, and assuming the truck operates under common highway conditions with an average load, we can refer to general guidelines and studies that suggest a stopping distance of several hundred feet for trucks traveling at highway speeds.
Regarding physics, as speed increases, the kinetic energy (KE) of a truck increases exponentially since KE = 1/2 mv^2, where m is the mass and v is the velocity. Therefore, more work (force applied over distance) is required to stop the vehicle, explaining why stopping distances can become significantly longer at higher speeds. It's worth noting that the longer distance is also due to the increased time it takes for the driver to react at higher speeds.
Based on these considerations, an appropriate educated guess for a fully loaded truck to stop at 55 mph would be greater than 100 feet. However, for the options provided (A. 1000 feet B. 1200 feet C. 1500 feet D. 1800 feet), choice D. 1800 feet may well represent a conservative estimate encompassing reaction time and braking distance under various conditions.
