Final answer:
If the trailer and the combination weigh 3000 pounds or less and are traveling at 20 mph, the combination must be able to stop within a certain distance. This stopping distance can be calculated by considering the reaction time of the driver and the braking distance of the vehicle.
Step-by-step explanation:
In order for a combination of a trailer and a vehicle to stop within a certain distance, it is important to consider several factors, including the weight of the combination and the speed at which it is traveling. According to the given information, if the trailer and the combination weigh 3000 pounds or less and are traveling at 20 mph, the combination must be able to stop within a certain distance. To calculate this distance, we need to know the reaction time of the driver and the braking distance of the vehicle.
For example, let's assume a reaction time of 1 second and a braking distance of 30 feet. The total stopping distance would be the sum of the distance covered during the reaction time and the braking distance. Assuming the vehicle is traveling at a constant speed of 20 mph (29.33 feet per second), during the 1-second reaction time, the vehicle would cover a distance of 29.33 feet. Adding this to the braking distance of 30 feet, the total stopping distance would be 59.33 feet.
Therefore, if the combination weighs 3000 pounds or less and is traveling at 20 mph, it must be able to stop within approximately 59.33 feet.