Final answer:
A tractor-trailer requires more distance to stop than an automobile due to its larger mass. The stopping distance includes both the distance covered during the driver's reaction time and the distance required to decelerate the vehicle to a halt.
Step-by-step explanation:
Based on braking studies, a tractor-trailer traveling at 55 mph requires more distance to stop compared to an automobile. This is because the stopping distance is affected by the mass of the vehicle, with heavier vehicles requiring more distance to come to a full stop. The stopping distance for any vehicle is a product of the driver's reaction time and the actual braking distance. The reaction time is generally constant (assuming a 0.500 s reaction time), during which the vehicle travels at its initial speed. After the driver hits the brakes, the braking distance is determined by the rate at which the vehicle can decelerate. Since a tractor-trailer is much heavier than a regular automobile, it takes a significantly longer distance to stop, especially when traveling at high speeds.
In the case of the last example given where a truck travels at 10 m/s with a reaction time of 0.5 seconds, we can deduce the stopping distance by calculating the distance covered during the reaction time (which is velocity multiplied by reaction time) and then adding the distance it takes to stop from the initial velocity at a given negative acceleration (due to braking).