Final answer:
The final velocity of the truck driver does not change after making a U-turn and driving in the opposite direction.
Step-by-step explanation:
The final velocity of the truck driver does not change after making a U-turn and driving in the opposite direction. While the truck's speed changes, the velocity remains the same because velocity takes into account both the speed and direction of motion. Since the speed remains constant at 30 mph and the direction changes, the velocity is still 30 mph, just in the opposite direction.