Final answer:
The car's average velocity is 199.58 km/h south, calculated by converting 31 miles to kilometers and 30 minutes to hours, then dividing the distance by the time.
Step-by-step explanation:
To find the car's velocity during the trip, we will use the definition of average velocity, which is the total displacement divided by the time taken for the trip. Since the car is traveling south on I-79 and there are no indicators of changes in direction, we can assume that the displacement and distance are the same. Thus, the car's average velocity equals its speed because it's moving in a straight line.
The car travels 31 miles in 30 minutes. To express velocity in a standard unit, we convert miles to kilometers (1 mile = 1.60934 kilometers) and 30 minutes to hours (30 minutes = 0.5 hours).
Thus, the car's velocity is:
Velocity = distance / time = (31 miles * 1.60934 km/mile) / 0.5 hours = 99.79 km / 0.5 hours = 199.58 km/h south.