A car travels 95 km to the north at 70.0 km/h,then turns around and travels 21.9 km at 80.0 km/h.What is the difference between the average speed and the average velocity on this trip?

Question

Quizplus · Accepted Answer

The average speed is the total distance divided by the total time, while the average velocity is the total displacement divided by the total time. The total distance is 95 km + 21.9 km = 116.9 km. The total displacement is 95 km - 21.9 km = 73.1 km. The time for the first part is 95 km / 70 km/h = 1.357 hours, and for the second part is 21.9 km / 80 km/h = 0.274 hours. Total time is 1.357 + 0.274 = 1.631 hours. Average speed = 116.9 km / 1.631 h = 71.7 km/h. Average velocity = 73.1 km / 1.631 h = 44.8 km/h. The difference is 71.7 km/h - 44.8 km/h = 26.9 km/h, approximately 27 km/h.

A Car Travels 95 Km to the North at 70